Sally walks to the store at a rate of 3 m/s for 15 seconds. She stops at a crosswalk for 4 seconds until the sign tells her she can go. Sally ran across the street at 5 m/s for 3 seconds until she reached the other side. She then walked the rest of the way to the store at 3 m/s. If the store was 100 m away from where Sally started originally and it took her 250 seconds to get there, what was her average speed?
Answer:
Average speed= 0.4 m/sExplanation:
step one:
simply put average speed is defined as the total distance travelled divided by the total time taken.
step two:
given data
total distance is the distance from where she started to the store
which is 100 m
also, we are told that the total time taken is 250 seconds
step three:
Hence we can compute the average speed as
average speed= 100/250
average speed= 0.4 m/s
If a 500kg elephant is sliding across a frictionless patch of ice, how much force is needed to keep the elephant from slowing down?
Answer:
4905NExplanation:
The force needed to keep the elephant from slowing down is expressed as shown according to Newtons second law of motion.
Force = mass * acceleration due to gravity
Given
Mass of elephant = 500kg
acceleration due to gravity = 9.81m/s²
Force = 500*9.81
Force = 4905N
Hence the force needed to keep the elephant from slowing down is 4905N
a) How long (in ns) does it take light to travel 1.0 m in a vacuum?
b) What distance does light travel in water, glass, cubic zirconia during the time it travels in 1.0 m vacuum?
Answer:
a
[tex]t = 3.33 \ ns[/tex]
b
i [tex]D_w =0.75 \ m [/tex]
ii [tex]D_g =0.67 \ m [/tex]
iii [tex]D_c =0.46 \ m [/tex]
Explanation:
Generally the time taken to travel 1 m in a vacuum is mathematically represented as
[tex]t = \frac{1}{c}[/tex]
Here c is the speed of light with value [tex]c = 3.0*10^{8} \ m/s[/tex]
So
[tex]t = \frac{1}{3.0*10^{8}}[/tex]
[tex]t = 3.33*10^{-9} \ s[/tex]
[tex]t = 3.33 \ ns[/tex]
The distance light travels in water is mathematically represented as
[tex]D_w = \frac{c}{n_w} * t[/tex]
Here n_w is the refractive index of water with value 1.333
So
[tex]D_w = \frac{3.0*10^{8}}{1.333} * 3.33*10^{-9}[/tex]
[tex]D_w =0.75 \ m [/tex]
The distance light travels in glass is mathematically represented as
[tex]D_g = \frac{c}{n_g} * t[/tex]
Here n_g is the refractive index of glass with value 1.5
So
[tex]D_g = \frac{3.0*10^{8}}{1.5} * 3.33*10^{-9}[/tex]
[tex]D_g =0.67 \ m [/tex]
The distance light travels in cubic zirconia is mathematically represented as
[tex]D_c = \frac{c}{n_g} * t[/tex]
Here n_c is the refractive index of cubic zirconia with value 2.15
So
[tex]D_c = \frac{3.0*10^{8}}{2.15} * 3.33*10^{-9}[/tex]
[tex]D_c =0.46 \ m [/tex]
An external reward is known as extrinsic motivation.
ОА.
True
OB. False
how to find range with height and velocity
Answer:
[tex]R= \frac{ v_ i\: ^2\:\times sin\:20}{g}[/tex]
Explanation:
What acceleration would a 18 kg box have if we pushed it with a force of 250 N across a surface that
has a coefficient of friction of 0.8?
N
Answer:
[tex]a=0.08\ m/s^2[/tex]
Explanation:
Given that,
Mass of a box, m = 18 kg
It is pushed with a force of 250 N
The coefficient of friction is 0.8
We need to find the acceleration of the box.
Normal force acting on the box,
N = mg
M = 18 × 10
N = 180 N
The force acting on the force in terms of coefficient of friction is given by :
[tex]F=\mu mg\\\\\text{or}\\\\ ma=\mu mg\\\\a=\dfrac{\mu }{g}\\\\a=\dfrac{0.8}{10}\\\\a=0.08\ m/s^2[/tex]
So, the acceleration of the box is [tex]0.08\ m/s^2[/tex]
You drop a ball from a window located on an upper floor of a building. It strikes the ground with speed v. You now repeat the drop, but you ask a friend down on the ground to throw another ball upward at speed v. Your friend throws the ball upward at the same moment that you drop yours from the window. At some location, the balls pass each other. Is this location.
Answer:
y = y₀ (1 - ½ g y₀ / v²)
Explanation:
This is a free fall problem. Let's start with the ball that is released from the window, with initial velocity vo = 0 and a height of the window i
y = y₀ + v₀ t - ½ g t²
y = y₀ - ½ g t²
for the ball thrown from the ground with initial velocity v₀₂ = v
y₂ = y₀₂ + v₀₂ t - ½ g t²
in this case y₀ = 0
y₂2 = v t - ½ g t²
at the point where the two balls meet, they have the same height
y = y₂
y₀ - ½ g t² = vt - ½ g t²
y₀i = v t
t = y₀ / v
since we have the time it takes to reach the point, we can substitute in either of the two equations to find the height
y = y₀ - ½ g t²
y = y₀ - ½ g (y₀ / v)²
y = y₀ - ½ g y₀² / v²
y = y₀ (1 - ½ g y₀ / v²)
with this expression we can find the meeting point of the two balls
Mathew has a filtration kit, which consists of a funnel, a flask, and filter papers. Which of these mixtures can he separate using filtration?
Answer:
C. Muddy Water
Love, which can't be observed or measured directly, is an example of a psychological construct.
Please select the best answer from the choices provided
О Тrue
O False
Answer:
True
Explanation:
A psychological construct can't be observed and you can feel this,
Example: anxiety, anger, sadness
Question
In order for work to be done, what three things are necessary
How much power is needed to lift the 200-N object to a height of 10 m in 4 s?
Answer:
500 watts
Explanation:
Recall that the definition of power is the amount of energy delivered per unit of time.
In our case, the energy delivered is potential energy which we can estimate as the product of the weight of the object times the distance it is lifted above ground:
200 N x 10 m = 2000 Nm
then the power is the quotient of this potential energy divided the time it took to lift the object to that position:
Power = 2000 / 4 Nm/s = 500 Nm/s = 500 watts
Convert 580 g to kg.
The Answer Is - 0.58 Kilogram's
Hope This Help's
• Answer:
0.58 kg
• Explanation:
1 kg = 1000 g
580 g = 0.58 kg
A Van de Graaff generator is charged so that a proton at its surface accelerates radially outward at 1.35 ✕ 1012 m/s2. Find the following. (a) the magnitude of the electric force on the proton at that instant magnitude N direction ---Select--- (b) the magnitude and direction of the electric field at the surface of the generator magnitude N/C direction ---Select---
Answer:
(a).
We know that force is
F = m a
So
F = (1.67 x 10^(-27) x (1.38 x10^12)
F = 2.3 x 10^-15 N facing the radially outward direction
(b).
Similarly Force for charge is
F = q E = m a
So relating
E = F/q = 2.3x 10^-15 /(1.6 10^ -19
E = 144.75 N/C facing the radially outward direction
The answer to the question is
(a) The force on the proton is [tex]2.254\times10^{-15}\,N[/tex] directed radially outwards.
(b) The electric field at the surface of the generator is [tex]14031.25\, N/C[/tex] directed radially outwards.
The answer can be explained as shown below.
Given that a proton accelerates radially outward at [tex]1.35\times 10^{12}\,m/s^2[/tex].
ie; [tex]a=1.35\times 10^{12}\,m/s^2[/tex]We know the mass of a proton, [tex]m_p = 1.67\times10^{-27}\,kg[/tex].From Newton's second law we have,
[tex]F=mg[/tex]But here, [tex]m=m_p[/tex]
So, the electric force on the proton is;
[tex]F = m_p\, a= (1.67\times10^{-27}\,kg)\, \times(1.35\times 10^{12}\, m/s^2)=2.254\times10^{-15}\,N[/tex]The force on the proton is [tex]2.254\times10^{-15}\,N[/tex] directed radially outwards.Also, we know that, in electrostatics,
[tex]F=Eq\\ \\\implies E=\frac{F}{q}[/tex]The charge of a proton is, [tex]q=1.6\times 10^{-19}\,C[/tex]Therefore, the electric field is given by,
[tex]E=\frac{2.254\times 10^{-15}N}{1.6\times 10^{-19}\,C} = 14031.25\, N/C[/tex]The electric field at the surface of the generator is [tex]14031.25\, N/C[/tex] directed radially outwards.Learn more about the electric force here:
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A river flows from south to north at 5.6 km/hr. On the west bank of this river, a boat launches and travels perpendicular to the current with a velocity of 7.7 km/hr due east. If the river is 1.6 km wide at this point, how far downstream does the boat land on the east bank of the river relative to the point it started at on the west bank?
Answer:
Downstream displacement = 1.1648 km
Explanation:
Given:
Speed of flow = 5.6 km/h
Speed of current upstream = 7.7 km/h
Increase in size = 1.6 km wide
Computation:
Total time to cross = Increase in size / Speed of current upstream
Total time to cross = 1.6 / 7.7
Total time to cross = 0.208 h
Downstream displacement = Speed of flow × Total time to cross
Downstream displacement = 5.6 × 0.208
Downstream displacement = 1.1648 km
Which term describes the tendency of an object to resist changes in motion?
A) reaction
B) force
C) inertia
D) acceleration
Answer:
inertia
Explanation:
Where do you feel that you are traveling at the fastest speed when on the swing?
Answer:
C
Explanation:
I think it's C, because at that point, you are going fastest. Sorry if im wrong, hope this helps.
Answer:
In between and the middle one
Explanation:
What does a diagonal upward sloping line on a position time graph mean?
diagonal line means the velocity is constant.
5. A projectile is fired in Earth's gravitational field with a horizontal velocity of y = 9.00 m/s.
b. How far does the projectile fall in the vertical direction in 0.550 s?
Answer:
4.13mExplanation:
Given
Horizontal velocity = 9.00m/s
time taken = 0.550 s
Required
How far does the projectile fall in the vertical direction
Using the formula for finding the maximum height of the projectile
H = U²sin²θ/2g where;
U = 9.00m/s
θ = 90° (object launched in the vertical direction)
g = 9.81m/s²
Substituting the given parameters into the formula;
H = 9²sin²90/2(9.81)
H = 81(1)/19.62
H = 81/19.62
H = 4.128 m
H ≈ 4.13m
Hence the distance that the projectile fall in the vertical direction is 4.13m
is it true or false if a force is a push or a pull on a object
Answer: true
Explanation: a force can be anything that effects an object, as long as the object moves
Two identical pellet guns are fired simultaneously from the edge of a cliff. These guns impart an initial speed of 23.7 m/s to each pellet. Gun A is fired straight upward, with the pellet going up and then falling back down, eventually hitting the ground beneath the cliff. Gun B is fired straight downward. In the absence of air resistance, how long after pellet B hits the ground does pellet A hit the ground
Answer:
Ta - Tb = 4.84 sec (approx)
Explanation:
Time taken by A = Time taken By B + Extra time
Ta - Tb = T
We know that
Time (T) = [v-u] /a ...................[a=9.8 m/s²]
So,
Ta - Tb = [v-u] /a
Ta - Tb = [-23.7-23.7] /9.8
Ta - Tb = 4.8367 sec
Ta - Tb = 4.84 sec (approx)
How many Newtons of force does it take to move a 53 kilogram object?
Two point charges are on the x-axis. One charge, q1 = 10 nC, is located at the origin, and the othercharge, q2 = 18 nC, is located at x = 9.0 m. What is the force on q2?a) 20 nN in the positive x-directionb) 20 pN in the positive x-directionc) 20 nN in the negative x-directiond) 20 pN in the negative x-directione) 180 nN in the positive x-direction
Answer:
The correct option is A
Explanation:
Generally the force on [tex]q_2[/tex] is mathematically represented as
[tex]F_2 = \frac{ k * q_1 * q_2 }{ x^2}[/tex]
here k is the coulombs constant with value [tex]k = 9*10^{9}\ kg\cdot m^3\cdot s^{-4} \cdot A^{-2}.[/tex]
=> [tex]F_2 = \frac{ 9*10^{9} * 10*10^{-9} * 18*10^{-9} }{ 9^2}[/tex]
=> [tex]F_2 = 2*10^{-8} \ N[/tex]
=> [tex]F_2 = 20*10^{-9} \ N[/tex]
=> [tex]F_2 = 20nN[/tex]
The direction is in the positive x-axis because both charge are of the same polarity so the will repel hence [tex]q_2[/tex] will move toward the positive x-axis
20. Convert 36 km/hr to m/s.
What are 3 ways a car can accelerate? (CRE)
The three ways a car can accelerate are change in velocity, change in direction, or both.
What is acceleration?The rate of velocity change concerning time is known as acceleration. The acceleration of the object is;
[tex]\rm a = \frac{v-u}{t}[/tex]
Here,
a is the acceleration
v is the final velocity
u is the initial velocity
t is the period
The three ways a car can accelerate are as follows;
a)Change in velocity.
b)Change in direction
c)Change in both velocity and direction.
Hence, the three ways a car can accelerate are change in velocity, change in direction, or both.
Learn more about acceleration, here:
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Please answer the question on the bottom
Answer:
the one with 2 batteries
An object accelerates at 20 m/s2. By how much does the speed change in one second?
Explanation:
a= v/t
v= at
= 20m/s2 × 1sec
= 20m/s
How much work must be done to stop a 1150 kg car traveling at 120 km/h?
Answer:
The work to be done is 638,761.12 J
Explanation:
Given;
mass of the car, m = 1150 kg
velocity of the car, v = 120 km/h = 33.33 m/s
Apply work energy theorem;
W = K.E
where;
W is the work done
K.E is the kinetic energy
W = ¹/₂mv²
W = ¹/₂ (1150)(33.33)²
W = 638,761.12 J
Therefore, the work to be done is 638,761.12 J
Which inference about Arthur is supported by the text?
Fossil fuels like gasoline or coal are examples of
Answer:
Nonrenewable Resources
Answer:
fossil fuels
Explanation:
Genes are section of DNA that code for a particular trait. Genes are
Answer:
a gene is the basic physical and functional unit of heredity.
Genes are section of DNA that code for a particular trait. Genes are basic unit of inheritance in all living things specifying the physical and biological traits.
What are genes ?The precise meaning of the term "gene" has long been a topic of discussion in science. Here's an easy way to think about it: Our cells and tissues are built with proteins as the foundation. And genes are the area of our genome where the instructions for constructing those proteins are stored.
For instance, the human genome has over 20,000 genes that code for proteins. It's interesting to note that just 1.5% of the complete human genome contains all of the information for those 20,000 protein-coding genes.
A broader definition of a gene includes DNA sequences, sometimes called RNA genes, that include instructions for building an RNA molecule that performs a function other than directly encoding a protein.
Find more on genes:
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