A pitcher throws a 0.143-kg baseball toward the batter so that it crosses home plate horizontally and has a speed of 42 m/s just before it makes contact with the bat. The batter then hits the ball straight back at the pitcher with a speed of 49 m/s. Assume the ball travels along the same line leaving the bat as it followed before contacting the bat. If the ball is in contact with the bat for 0.005 0 s, what is the magnitude of the average force exerted by the bat on the ball?

200N appox

Explanation:

Step one:

Given data

mass of ball= 0.143kg

initial velocity of ball u= 42m/s

final velocity of the ball= 49m/s

time of impact= 0.005s

Step two

From the relation Ft=mΔv

we can find the average force as

F=mΔv/t

substitute

F=0.143*(49-42)/0.005

F=0.143*7/0.005

F=1.001/0.005

F=200.2

F= 200N appox

The average force is  200N

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.