If a pitcher throws a 120 m/s fastball how much force does he need to apply if he is in contact with the ball for 1.5 seconds

Force on the fast ball is given as

here m = mass of the ball

Explanation:

As we know that initially fast ball is moving with speed 120 m/s

now after force applied to the ball it comes to rest

So final speed of the ball is ZERO

now time interval of applied force is

t = 1.5 s

now we have

Now as per Newton's II law we know

here m = mass of the ball

the bal will not change its velocity.

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.