motion

Question 1

what is speed

Answer 1

the distance moved by an object each second

Question 2

formula for average speed

Answer 2

total distance/total time taken

Question 3

what is the difference between speed and velocity

Answer 3

speed is a scalar (only has a magnitude) and velocity is a vector (magnitude and direction)

Question 4

formula for velocity

Answer 4

displacement/time

Question 5

what is acceleration

Answer 5

rate of change of velocity

Question 6

formula for acceleration

Answer 6

change in velocity/time taken

or

a = (v-u)/t

Question 7

distance time graph what does a straight horizontal line mean

Answer 7

stationary

Question 8

distance time graph what does a straight line in 45 degree angle mean

Answer 8

constant speed

Question 9

what does the gradient show in a distance time graph

Answer 9

if it goes up the object is speeding up and vice versa

Question 10

distance time graph what does it mean if the line is going down

Answer 10

the object is moving backwards or returning to its original position

Question 11

velocity/speed time graph what does horizontal straight line mean

Answer 11

velocity is constant (no acceleration)

Question 12

velocity/speed time graph what does a line sloping mean

Answer 12

object is accelerating if it slopes upwards and vice versa

Question 13

how to get the distance travelled in a speed-time graph

Answer 13

find the area under the graph

Question 14

what is the gradient of a speed time graph

Answer 14

the acceleration, if the gradient of the line changes then the acceleration changes

Question 15

what is freefall speed

Answer 15

acceleration of freefall for a body near to the Earth is constant and equal to approximately 10m/s^2

Question 16

what is freefall without air resistance

Answer 16

• the speed of a falling object will increase at a steady rate, getting larger the longer it falls for
• the only force acting on the object will be the weight of the object acting downwards

Question 17

what is freefall with air resistance

Answer 17

air resistance increases as the object falls until it is equal to the force of the weight of the object acting downwards. This means there is no resultant force acting on the skydiver and he then falls at a constant speed called the terminal speed/velocity