P1-Edexcel - Acceleration

Question 1

What is acceleration?

Answer 1

Acceleration is the change in velocity in a certain amount of time.

Question 2

What is the equation used to find the average acceleration of an object?

Answer 2

a = (final velocity - initial velocity) / time (s) or, a = (v - u) / t

Question 3

What is deceleration?

Answer 3

Deceleration is negative acceleration (if something slows down, the change in velocity is negative).

Question 4

Give the step-by-step method to find the average acceleration.
Question: A car is travelling at 15 m/s, when it collides with a tree and comes to a stop. Estimate the deceleration of the car.

Answer 4

1) Estimate how long it would take the car to stop.
‘The car comes to a stop in ~1s (~ means an approximate value)
2) Put these numbers into the acceleration equation.
a = (v - u) / t
a = (0 - 15) / 1
a = -15m/s squared.
3) Because the car has slowed down, the acceleration would be negative so the car would be decelerating.

Question 5

What is uniform acceleration?

Answer 5

Speeding up/slowing down at a constant rate.

Question 6

What is the equation used to find uniform acceleration?

Answer 6

V squared - U squared = 2 x a x X
(a = acceleration)
(X = distance)

Question 7

Give the step-by-step equation to find uniform acceleration.
Question: A van travelling at 23 m/s starts decelerating uniformly at 2.0 m/s as it heads towards a built-up area 112 m away. What will its speed be when it reaches the built-up area?

Answer 7

1) First, rearrange the equation so V squared is on one side.
V squared = U squared + (2 x a x X)
2) Now put the numbers in the equation, a will be negative because it’s deceleration.
V squared = 23 squared + (2 x -2.0 x 112)
=81
3) Finally square root the whole thing.
V = square root of 81 = 9 m/s