Kinematics help for AP Physics B?

Question

A ball rolls off a table and falls 0.68 m to the floor, landing with a speed of 5.5 m/s.

(a) What is the magnitude of the acceleration of the ball just before it strikes the ground? (Ans. 9.81)

(b) What was the initial speed of the ball?

(c) What initial speed must the ball have if it is to land with a speed of 6.1 m/s?

Answer 1

Your working formula is

Vf^2 - Vo^2 = 2gs

where

Vf = final velocity = velocity of ball as it hits the floor = 5.5 m/s (given)

Vo = initial velocity = 0 (as ball simply rolls off the table)

g = acceleration due to gravity

s = distance that ball has to travel = 0.68 m (given)

<<  What is the magnitude of the acceleration of the ball just before it strikes the ground? >>

Substitute appropriate values and solve for "g"

<<  What was the initial speed of the ball? >>

Initial speed of ball is equal to zero (since it simply rolled off the table).



<< What initial speed must the ball have if it is to land with a speed of 6.1 m/s? >>

Substitute

Vf = 6.1

g = 9.8

s = 0.68

in the above formula and solve for Vo.

Hope this helps.

Answer 2

Why would you ask for help on your math homework online? You should at least try to figure it out,ask your teacher,or pay more attention in class.