The kinetic energy of the block when it reaches the bottom is 39.2 J.
<h3>
Kinetic energy of the block at the bottom</h3>
Apply the principle of conservation of energy.
K.E(bottom) = P.E(top)
P.E(top) = mgh
where;
- m is mass of the block
- g is acceleration due to gravity
- h is the vertical height of fall
P.E(top) = 5 x 9.8 x 0.8
P.E(top) = K.E(bottom) = 39.2 J
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A. I believe this might be the answer but
6 J/60 J= .1
.1 x 100= 10%
b. I'm not sure of this question
19. I'm not sure if I did this correct way or if there is a better way (I'm rusty)
300 J/.50 %= 600
600/100= 6 (answer)
20. (200 J)(.75%) = 150 (answer)
Check:
Efficiency: output/input x 100
150 J/200 J= .75
.75 x 100= 75%
Answer:
<h3>F = 35.84N</h3>
Explanation:
Force = mass * acceleration (Newton's second law of motion)
Given
Mass = 32kg
Get the acceleration using the expression d = 1/2at^2
3.5 = 1/2 (a)2.5^2
3.5 = 3.125a
a = 3.5/3.125
a = 1.12m/s^2
Get the net force;
F = 3.2 * 1.12
F = 35.84N
Hence the net force used to accelerate is 35.84N
When solving question that contains equations and the use mathematical computations, It is always ideal to list the parameters given.
Now, given that:
- the speed of the car which is the initial velocity (u) = 100 km/h before it hits the wall.
- after hitting the wall, the final velocity will be (v) = 0 km/h
Assumptions:
- Suppose we make an assumption that the distance travelled during the collision of the car with the brick wall (S) = 1 m
- That the car's acceleration is also constant.
∴
For a motion under constant acceleration, we can apply the kinematic equation:

where;
v = final velocity
u = initial velocity
a = acceleration
s = distance
From the above equation, making acceleration (a) the subject of the formula:


The initial velocity (u) is given in km/h, and we need to convert it to m/s as it has an effect on the unit of the acceleration.
since 1 km/h = 0.2778 m/s
100 km/h = 27.78 m/s


a = - 385.86 m/s²
Similarly, from the kinematic equation of motion, the formula showing the relation between time, acceleration and velocity is;
v = u + at
where;
v = 0
-u = at


t = 0.07 seconds
An airbag is designed in such a way as to prevent the driver from hitting on the steering wheel or other hard substance that could damage the part of the body. The use of the seat belt is to keep the driver in shape and in a balanced position against the expansion that occurred by the airbag during the collision on the brick wall.
Thus, we can conclude that the airbag must be inflated at 0.07 seconds faster before the collision to effectively protect the driver.
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Answer:
The idea that hard work is the most important aspect of new inventions existed before Edison gave his quote, however.
The idea behind this quote is that it is easy to have a good idea, or a creative insight. However, to follow through with that idea, and turn it into a reality, takes a level of patience and dedication that few people have.
Explanation: