a player kick a soccer ball which was any Tally at rest he imported an acceleration of 20 metre per second to to the wall calculate the magnitude of the change in velocity at the Inn 2s is and 5s is
Answers
We take the force to be in the positive direction, at least for earlier times. Then the impulse is
=9.0N⋅s
(b) Since J=F
avg
(c) To find the time at which the maximum force occurs, we set the derivative of F with respect to time equal to zero, and solve for t. The result is t=1.5×10
−3
s . At that time the force is
(d) Since it starts from rest, the ball acquires momentum equal to the impulse from the kick. Let m be the mass of the ball and ν its speed as it leaves the foot. Then,
ν=
m
o
=
m
J
=
0.45kg
9.0N⋅s
=20m/s
The force as function of time is shown below. The area under the curve is the impulse J. From the plot, we readily see that F(t) is a maximum at t=0.0015s , with F
max
=4500N