Forces and motion

Question 1

What is distance?

Answer 1

• total length of the path travelled by a moving object from start to finish

Question 2

What is displacement?

Answer 2

• the shortest distance between the start and finish points of a moving object

Question 3

What types of quantities are distance and displacement?

Answer 3

• distance = scalar
• displacement = vector

Question 4

What happens to the displacement of an object if they start and end at the same place?

Answer 4

• it will be zero

Question 5

Can displacement have a negative value?

Answer 5

• yes, depends on the direction moved

Question 6

What factors could affect the speed of someone walking, running or cycling?

Answer 6

• age
• terrain
• fitness
• distance travelled

Question 7

What kind of quantity is speed?

Answer 7

scalar

Question 8

What is the typical speed of a person walking in m/s?

Answer 8

1.5 m/s

Question 9

What is the typical speed of a person running in m/s?

Answer 9

3 m/s

Question 10

What is the typical speed of a person cycling in m/s?

Answer 10

6 m/s

Question 11

What is the typical speed of a car in m/s?

Answer 11

13-31 m/s

Question 12

What is the typical speed of a train in m/s?

Answer 12

50 m/s

Question 13

What is the typical speed of a plane in m/s?

Answer 13

250 m/s

Question 14

What is the typical speed of sound in m/s?

Answer 14

330 m/s

Question 15

How do you calculate distance travelled?

Answer 15

distance travelled = speed x time
s = v x t

distance in metres
speed in m/s
time in seconds

Question 16

What is velocity?

Answer 16

speed in a given direction

Question 17

How could velocity be influenced by defining the direction?

Answer 17

car driving 20m/s to the right
car driving -20m/s to the right (the car is heading left)

Question 18

Why does the velocity constantly change when an object moves in a circle?

Answer 18

• direction constantly changes
• constant speed, changing velocity

Question 19

How do you calculate the gradient/ speed of an object using a distance-time graph?

Answer 19

speed/ gradient = change in distance/ change in time

Question 20

How do you find the speed of an accelerating object in a distance- time graph?

Answer 20

• draw tangent to the graph
• find gradient of tangent

Question 21

How do you calculate acceleration?

Answer 21

acceleration = change in velocity/ time taken

a = m/s^2
∆v = m/s
t = s

Question 22

describe the movement and forces of an object falling through a liquid

Answer 22

• initially accelerates
• velocity increrases = drag increases
• resultant force = 0
• object moves at constant speed in one direction
• constant speed = terminal velocity

Question 23

What is terminal velocity?

Answer 23

the highest speed an object can go under a certain condition

Question 24

Describe the forces acting on a skydiver that jumps out of an aeroplane

Answer 24

1) maximum acceleration, no drag. large downwards resultant force (jump)
2) accelerates at decreasing rate, drag < weight, small downwards resultant force (1 min of free fall)
3) reaches terminal velocity, drag = weight, no resultant force

Question 25

What does a straight line upwards represent in a velocity-time graph?

Answer 25

• object accelerates and speeds up

Question 26

What does a curved line represent in a velocity time graph?

Answer 26

• acceleration decreases

Question 27

What does a horizontal line represent in a velocity- time graph?

Answer 27

• terminal velocity reached
• acceleration = 0