Atennis pro throws a tennis ball at a speed of 204 km/hr. a) the tennis racquet contacts the 0.057 kg ball for 0.25 s, therefore what is the average force on the ball?
b) the ball doesn't get slowed down by drag or friction, and the opponent returns the ball at a speed of 80 km/hr. assuming a contact time of 0.25 s, what average force is applied to the ball by the opponent’s racquet?

12.92 N, 17.98 N

Explanation:

Given

Speed of ball

mass of ball (m)=0.057 kg

time (t)=0.25 s

(a)Average Force(F)

=12.92 N

(b)Intial velocity(u)

Final velocity (v)

Average Force

F=17.984 N

its a 5.5 n

glad that

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