A ball starts at rest and rolls down a ramp, developing a speed of 45 m/s in 7 seconds. Calculate the ball's acceleration.

6.429 m/s^2.

Explanation:

Using equations of motion,

i. vf = vi + at

ii. vf^2 = vi^2 + 2a*S

iii. S = vi*t + 1/2 * (a*t^2)

Where,

vf = final velocity of the motion

vi = initial velocity of the motion

S = distance travelled

t = time taken to complete the motion

a = acceleration due to gravity

Given:

vi = 0m/s

vf = 45 m/s

t = 7 s

a = ?

Using the i. equation of motion,

vf = vi + at

45 = 0 + a*7

a = 45/7

= 6.429 m/s^2

what type of charge does it have? negative

no

sodium is solid at rt