The answer is c. the force of his swing
At the time of the impact, there is a collision between two bodies moving in opposite directions.
The force exerted on the ball causes the change of velocity.
This is simple as power in watts is equal to joules per second so we can do 1500 joules divided by 30 seconds which equals 50 watts
On Earth, gravity adds 9.8 m/s to the downwsrd speed of any falling object, every second. Beginning from zero downward speed, the speed grows to (8 x 9.8) = 78.4 m/s downward after 8 sec.
The doppler effect is the increase or decrease in the frequency of sound, light, or other waves as the source and observer move toward or away from each other.
-- You and your partner both get the same job to do:
Each of you gets a pallet of bricks, and you have to
put the bricks up on the bed of a truck, by hand.
Both pallets have the same number of bricks.
The pallet is way too heavy to lift, so you both cut the bands
that hold the bricks, and you lift the bricks from the pallet onto
the truck, by hand, two or three or four bricks at a time.
-- You get your pallet of bricks onto the truck in 45 minutes.
-- Your partner gets his pallet of bricks onto the truck in 3 days.
-- Work = (force) times (distance).
You and your partner both lifted the same amount of weight
up to the same height. You both did the same amount of work.
-- Power = (work done) divided by (time it takes to do the work) .
Your partner took roughly 96 times as long as you took
to do the same amount of work.
You did it faster. He did it slower.
You produced more power. He produced less power.
