Chapter 3 Motion

Question 1

What does the gradient of a distance time graph tell us?

Answer 1

It tells us the speed

Question 2

How is the instantaneous speed found from a distance time graph?

Answer 2

A tangent is drawn to the graph and the gradient of the tangent is the instantaneous speed

Question 3

What is the equation to find average velocity?

Answer 3

Avg Velocity = Change in Displacement / Time

Question 4

What is the difference between a distance-time graph and a displacement-time graph?

Answer 4

The distance in a distance time graph always increases

Question 5

What can not be found from a distance time graph?

Answer 5

The velocity

Question 6

What does the gradient of a displacement-time graph represent?

Answer 6

The velocity

Question 7

What is the equation for acceleration?

Answer 7

Acceleration = Change in velocity / time

Question 8

What is the gradient of a velocity time graph?

Answer 8

The acceleration

Question 9

How do you find the displacement on an velocity-time graph?

Answer 9

The area under the graph

Question 10

What does each of the symbols in the SUVAT equation mean?

Answer 10

S = displacement
U = Starting Velocity
V = Final Velocity
A = Acceleration
T = Time

Question 11

What are the SUVAT equations?

Answer 11

v = u + at
s = ut + 0.5at^2
s = 0.5(u + v)t
v^2 = u^2 + 2as

Question 12

What is stopping distance a combination of?

Answer 12

Thinking distance and Braking distance

Question 13

What is the equation for thinking distance?

Answer 13

Thinking distance = Speed x Reaction time

Question 14

What is thinking distance?

Answer 14

This is the distance between when the driver sees a reason to stop and the moment they apply the brakes

Question 15

What is Braking distance?

Answer 15

This is the distance traveled from the time brakes are applied to when the vehicle stops

Question 16

What is the value of the acceleration due to gravity?

Answer 16

9.81ms-2

Question 17

What does the acceleration due to gravity apply to?

Answer 17

It applied to all objects with mass

Question 18

Does mass affect the acceleration of free fall?

Answer 18

No

Question 19

How can g be determined with a trap door?

Answer 19

Using an electromagnet and a trap door. A ball in a vacuum is held up by an electromagnet and then it is dropped and the timer is started. The timer is stopped when the ball passes through a trap door. Then the distance the ball has traveled is calculated and SUVAT is used to calculate the acceleration of free fall.

Question 20

What is a more accurate method of working out the value of g?

Answer 20

Using a stroboscope and a camera. The strobe offers regular intervals which are recorded on a camera. Then the change in the position of a dropped object is used to calculate g.

Question 21

What is the assumption made when calculating projectile motion?

Answer 21

Assumption: There is no air resistance

Question 22

How can the velocity at any point of a projectiles motion be calculated?

Answer 22

By drawing a tangent to the graph of the motion of the projectile and working out its magnitude

Question 23

How is the motion of a projectile analysed?

Answer 23

Using SUVAT for the x and y components