Question

Question 1 (1 point) There were 3 friends that decided to race their bikes down a hill without peddling. They all approached the top of the hill with a velocity of 2m/s. When they got down to the bottom of the hill 15 seconds later, they had achieved a velocity of 15m/s. To their surprise, they all made it down at the same time. What was their acceleration? a 1.15 m/s2 b 7.5 m/s2 c .87 m/s2 d 1 m/s2 Question 2 (1 point) What is the acceleration of a 450 horsepower race car if the car had a mass of 1000Kg and began at a velocity of 10m/s. After 1.75 sec., the car has a velocity of 45m/s? a 10 m/s2 b 25.71 m/s2 c 4.5 m/s2 d 20 m/s2 Question 3 (1 point) A car going 75 mph (35 m/s) hits a wall and comes to a stop. It takes 1.25 s for the car to come to a stop. What is the acceleration of the car? a -60 m/s2 b 60 m/s2 c -28 m/s2 d 28 m/s2 Question 4 (1 point) An Olympic skier starts from rest the top of a hill, accelerating down the hill until he comes to a turn 12 seconds later. his velocity at the turn is 55 m/s, what was his acceleration when he got to the turn? a -.22 m/s2 b .22 m/s2 c 4.58 m/s2 d -4.58 m/s2 Question 5 (1 point) A boy rolls a tennis ball down the hallway and it takes 4.5 seconds to come to a stop. If the ball started with a velocity of 17m/s, what was the acceleration of the ball? a 3.78 m/s2 b -3.78 m/s2 c -4.5 m/s2 d 0 m/s2

Answer 1

Answer:

Explanation:

For the questions we will be using the formula;

acceleration = change in velocity/Time

acceleration = v-u/t

v is the final velocity

u is the initial velocity

t is the time

1) v = 15m/s, u = 2m/s t = 15s

a = 15-2/15

a = 13/15

a = 0.87m/s²

Their acceleration was 0.87m/s²

2) u = 10m/s, v = 45m/s, t = 1.75s

a = 45-10/1.75

a = 35/1.75

a = 35/(175/100)

a = 35×100/175

a = 3500/175

a = 20m/s²

3) u = 35m/s, v = 0m/s (comes to a stop), t = 1.25m/s

a = 0-35/1.25

a = -35/1.25

a = -28m/s²

The acceleration of the car is -28m/s²

4) v =55m/s, u = 0m/s t = 12s

a = 55-0/12

a = 55/12

a = 4.58m/s²

His acceleration when he got to the turn is 4.58m/s²

5) u = 17m/s (starting velocity)

v = 0m/s (stopping velocity)

t = 4.5s

a = 0-17/4/5

a = -17/4.5

a = -3.78m/s²

The the acceleration of the ball was -3.78m/s²