P2.1 Forces

Question 1

Reaction Time

Answer 1

Reaction time could be created when using a stop watch, this may affect the accuracy and precision of your measurement

Question 2

Light gates

Answer 2

You can measure very short periods of time using light gates - it is a timer that starts and stops when an object interrupts a light beam.

Question 3

Ultra sound

Answer 3

You can use an ultrasound to measure distance. The device measures the time taken for a pulse to travel there and back. It uses this value, and the speed for the pulse, to work put the distance.

Question 4

Average speed formula

Answer 4

Average speed (m/s) = total distance (m) / total time (s)

Question 5

Vector

Answer 5

Force is a vector, you represent a vector with an arrow. The length of the arrow shows the magnitude, and the direction.

Question 6

Scalar

Answer 6

The measurement that you make with a stop clock is a scalar. It has a magnitude but no direction.

Question 7

Difference between speed and velocity?

Answer 7

Speed is a scalar quantity whereas velocity is a vector quantity so it has a magnitude and a direction.

Question 8

Define acceleration

Answer 8

Change in velocity per second

Question 9

Define uniform acceleration

Answer 9

When the acceleration does not change

Question 10

How to calculate acceleration

Answer 10

acceleration (m/s^2) = final velocity - initial velocity / time

Question 11

What does the line on a distance-time graph tell you?

Answer 11

Straight line - means the object’s speed is constant as the gradient (speed) does not change.
Horizontal line- means that the object is not moving.

The steeper the line, the faster the object is travelling.

Question 12

Formula for calculating speed from graph

Answer 12

Speed = change in distance / time

Velocity= change in displacement / time

Question 13

Kinetic energy formula

Answer 13

Kinetic energy (j) = 0.5 x mass (kg) x (speed (m/s))^2