P5 - Acceleration

Question 1

What is acceleration?

Answer 1

How quickly you are speeding up

(NOT THE SAME AS VELOCITY OR SPEED)

Question 2

What is uniform acceleration (aka constant acceleration) ?

Answer 2

Speeding up or slowing down at a constant rate

Question 3

What is the formula to find the average acceleration in an object?

Answer 3

change in velocity (m/s)
Acceleration (m/s2) = ———————————-
time (s)

(Abbreviated would be a = v / t)

Question 4

What is deceleration?

Answer 4

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

Question 5

NOTE : (NOT A QUESTION)

Answer 5

YOU MAY HAVE TO ESTIMATE THE ACCELERATION OR DECELERATION OF AN OBJECT.TO DO THIS REMEBER THE TYPICAL SPEEDS IN DISTANCE,DISPLACEMENT, SPEED AND VELOCITY

Question 6

A car is travelling along a road,when it collides with a tree and comes to a stop. ESTIMATE the deceleration of the car.

Answer 6

1) First give a sensible speed for the car to be travelling at (typical speed of a car is 25 m/s)

2) Next estimate how long it would take a car to stop ( 1 second )

3) Put these numbers into the acceleration equation ( a = v / t ) ( -25 / 1 = -25)

4) The question asked for the deceleration,so you can show the minus sign(which shows the car is slowing down)

(FINAL ANSWER IS ~25m/s2)

Question 7

What is acceleration due to?

Answer 7

It is due to gravity (g) is uniform for objects in free fall. It’s roughly equal to 9.8m/s2 near the Earths surface and has the same value as gravitational field strength

Question 8

What is the equation for uniform acceleration (aka constant acceleration) ?

Answer 8

Final velocity (m/s) - Initial velocity (m/s) = 2 x acceleration (m/s2) x distance (m)

(Abbreviated as v^2 -u^2 = 2as)

Question 9

What is initial velocity?

Answer 9

The starting velocity of an object

Question 10

A van travelling at 23 m/s starts decelerating uniformly at 2.0 m/s as it heads towards a built-up area 112m away.What will its speed be when it reaches the built-up area?

Answer 10

1) First rearrange the equation so v^2 is on one side (v^2 = u^2 + 2as)

2) Now put the numbers in - remember a is negative as its a deceleration ( 23^2 + (2 x 2.0 x 112)) = 81

3) Finally square root the whole thing (root of 81 = 9)

(FINAL ANSWER IS 9 m/s)