A roller coaster is stopped on a track. When the engineer presses a launch button on the coaster, the coaster moves forward. Explain this change in terms of balanced and unbalanced forces.
Answer:60 gm
Explanation:
Given
initial velocity of ball 
Force exerted by racquet 
time period of force 
final velocity of ball 
Racquet imparts an impulse to the ball which is given by



Answer:
The correct answer is d Both the observer's are correct
Explanation:
We know by postulates of relativity that laws of physics are same in different inertial frames.
Thus for each of the frames they make observations related to their frames and since the observations are true for their individual frames they both are correct. But when we compare the two frames we need to use transformation equations to compare both the results.
Answer:
cheetah goes 52.2 m in that time.
Explanation:
The original kinetic energy will be 0 J and the final kinetic energy will be 7500 J and the amount of work utilized will be similar to the final kinetic energy i.e., 7500 J.
<u>Explanation:</u>
As it is known that the kinetic energy is defined as the energy exhibited by the moving objects. So the kinetic energy is equal to the product of mass and square of the velocity attained by the car. Thus,

So the initial kinetic energy will be the energy exerted by the car at the initial state when the initial velocity is zero. Thus the initial kinetic energy will be zero.
The final kinetic energy is
= 7500 J
As the work done is the energy required to start the car from zero velocity to 5 m/s velocity.
Work done = Final Kinetic energy - Initial Kinetic energy
Thus the work utilized for moving the car is
Work done = 7500 J - 0 J = 7500 J
Thus, the initial kinetic energy of the car is zero, the final kinetic energy is 7500 J and the work utilized by the car is also 7500 J.