Part C: Quantitative Problems when vf is not 0

8. A 7 kg. bowling ball traveling down a lane at 8 m/s hits a wall, and after 0.05 seconds
rebounds at the same speed.

a. Find (delta)v and m(delta)v.

b. With what impact force did the bowling ball hit the wall?

(a)

(b)

1120 N

Explanation:

Change in velocity, is given by subtracting the initial velocity from the final velocity and expressed as

Where v represent the velocity and subscripts f and i represent final and initial respectively. Since the ball finally comes to rest, its final velocity is zero. Substituting 0 for final velocity and the given figure of 8 m/s for initial velocity then the change in velocity is given by

To find then we substitute 7 kg for m and -8 m/s for therefore

(b)

The impact force, F is given as the product of mass and acceleration. Here, acceleration is given by dividing the change in velocity by time ie

Substituting t with 0.05 s then

Since F=ma then substituting m with 7 Kg we get that F=7*-160=-1120 N

Therefore, the impact force is equivalent to 1120 N

electrical potential energy =0.072 j

explanation:

electrical potential energy is given by

u= q δv

q= charge=6 c

δv= potential difference and is given by

δv= e d

e= electric field

d= distance=5 mm=0.005 m

δv=2.4 (0.005)=0.012 v

now electric potential energy= u= q δv

u=6 (0.012)

u=0.072 j