# PHYSICS HELP?

Solve each problem using one or more of these equations. Show all work.

x= x0 + v0t + 1/2at^2

v= v0 + at

v^2 = v0^2 + 2a (x-x0)

g = 9.8 m/s^2 downward

1) An object accelerates from rest with a constant acceleration of 14.5 m/s^2, what will its velocity be after 92 s?

2) An object accelerates from rest to a velocity of 38 m/s over a distance of 12 m. What was its acceleration?

3) A sled with no initial velocity accelerates at a rate of 1.1 m/s^2 down a hill. How long does it take the sled to go 13m to the bottom?

4) An object is moving with an initial velocity of 34 m/s. It accelerates at a rate of 2.8 m/s^2 over a distance of 60m. What is its new velocity?

5) A ball rolls along the floor with a constant velocity of 3 m/s. How far will it have gone after 234 seconds?

6) A stomp rocket takes 2.4 seconds to reach its maximum height.

A. What was its initial velocity?

B. What was its maximum height?

### 1 Answer

- Anonymous1 month ago
1) An object accelerates from rest with a constant acceleration of 14.5 m/s^2, what will its velocity be after 92 s?

v= v0 + at = 0 + 14.5*92 = 1334 m/s

2) An object accelerates from rest to a velocity of 38 m/s over a distance of 12 m. What was its acceleration?

v^2 = v0^2 + 2a (x-x0)

a = (v^2 - v0^2) / [2(x - x0)] = (38^2 - 0) / [2*(12 - 0)] = 60.167 m/s^2

3) A sled with no initial velocity accelerates at a rate of 1.1 m/s^2 down a hill. How long does it take the sled to go 13m to the bottom?

x = x0 + v0t + 1/2at^2

x = 0 + 0*t + 1/2 a t^2

t = (2 x / a)^1/2 = (2*13 / 1.1)^1/2 = 4.86 s

4) An object is moving with an initial velocity of 34 m/s. It accelerates at a rate of 2.8 m/s^2 over a distance of 60m. What is its new velocity?

v^2 = v0^2 + 2a (x-x0)

v = [v0^2 + 2a (x-x0)]^1/2 = [34^2 + 2*2.8*(60 - 0)]^1/2 = 38.63 m/s

5) A ball rolls along the floor with a constant velocity of 3 m/s. How far will it have gone after 234 seconds?

x= x0 + v0t + 1/2at^2 = 0 + 3*234 + 0 = 702 m

6) A stomp rocket takes 2.4 seconds to reach its maximum height.

A. What was its initial velocity?

v = v0 + a t

v0 = v - a t = 0 - (-9.8)*2.4 = 23.52 m/s

B. What was its maximum height

x= x0 + v0t + 1/2at^2

x = 0 + 23.52*2.4 + 0.5*(-9.8)*2.4^2 = 28.22 m