Forces, Motion and Pressure ETT

Question 1

What two things does a force arrow show?

Answer 1

1. The length of the arrow shows the size of the force.
2. The direction of the arrow shows the direction of the force.

Question 2

Give some examples of non-contact forces

Answer 2

• Gravitational force
• Electrostatic force
• Magnetic force

Question 3

Give some examples of contact forces

Answer 3

• Friction
• Air resistance
• Tension
• Normal contact force

Question 4

What are the units for:

a) gravitational field strength
b) weight
c) mass

Answer 4

a) N/kg
b) N
c) kg

Question 5

What equation links weight, mass and gravitational field strength?

Answer 5

Weight = mass x gravitational field strength

W = m g

Question 6

What type of energy is stored in a spring that is stretched or compressed?

Answer 6

Elastic potential energy

Question 7

What happens to the temperature of an object experiencing friction?

Answer 7

Temperature increases

Question 8

What is the name of an object that:

a) will return to its original shape after being deformed
b) will not return to its original shape after being deformed

Answer 8

a) elastic
b) inelastic

Question 9

What is the relationship between force and extension of an elastic object?

Answer 9

Directly proportional

Question 10

What happens to air resistance as speed increases?

Answer 10

As speed increases, air resistance increases.

Question 11

What are typical speed values for someone walking, running and cycling (m/s)?

Answer 11

• Walking 1.5 m/s
• Running 3 m/s
• Cycling 6 m/s

Question 12

What is the speed of sound?

Answer 12

340 m/s

Question 13

How many forces need to to be applied to this spring to stretch or compress it?

Answer 13

Two forces (e.g. one at either end)

Question 14

What equation links distance travelled, speed and time?

Answer 14

Distance travelled = speed x time

s = v t

Question 15

When oil or grease is used to reduce friction, what is this called?

Answer 15

Lubrication

Question 16

Describe the motion in the following distance-time graph at point (a).

Answer 16

a) constant speed

Question 17

Describe the motion of a moving car experiencing balanced forces.

Answer 17

Keep moving at a constant speed

Question 18

Describe the motion of a moving car experiencing unbalanced forces.

Answer 18

The car will change speed (either accelerate or decelerate)

Question 19

Describe the motion of a stationary car experiencing balanced forces.

Answer 19

The car will remain stationary.

Question 20

Describe the motion of a stationary car experiencing unbalanced forces.

Answer 20

The car will accelerate.

Question 21

What are typical everyday speeds for cars, trains and planes?

Answer 21

• Car 25 m/s
• Train 55 m/s
• Plane 250 m/s

Question 22

If your mass on Earth is 50 kg, what would be your mass on the moon?

Answer 22

The same, 50 kg.

Your mass does not change.

Question 23

Name the equipment used to measure forces

Answer 23

Newtonmeter

Question 24

Name the forces acting on the book.

Answer 24

Weight (downwards)
Normal contact force (upwards)

Question 25

Describe the experiment to investigate how force affects the extension of the spring.

Answer 25

* Measure the starting length of the spring using the ruler. * Add one 10 g mass, measure the extension of the spring using the ruler. * Repeat 5 times, each time adding one 10 g mass and measuring the extension of the spring.

Question 26

What equation links force, distance and moment of a force?

Answer 26

Moment of a force = force x distance

Question 27

What is a moment?

Answer 27

A turning effect of a force

Question 28

What are the SI units for: a) moment b) force c) distance

Answer 28

a) newton-metres, Nm b) newtons, N c) metres, m

Question 29

If an object is balanced, what is true about the size of the clockwise and anti-clockwise moments?

Answer 29

They are equal in size.

Question 30

What equation links pressure, force and area?

Answer 30

Question 31

What two things does pressure in a liquid depend on?

Answer 31

* Depth * Density of the liquid

Question 32

What are the SI units for: a) Pressure b) Force c) Area

Answer 32

a) Pressure is measured in pascals (Pa) b) Force is measured in newtons (N) c) Area is measured in metres squared (m²)

Question 33

Describe and explain the relationship between the depth of a liquid and pressure.

Answer 33

* As depth increases, pressure increases. * Because, as depth increases, the number of particles above increases. * Pressure increases because of the increased weight of particles above.

Question 34

Describe the motion in the following distance-time graph at point (b).

Answer 34

b) stationary

Question 35

Describe the motion in the following distance-time graph at point (c).

Answer 35

c) accelerating

Question 36

Describe the motion in the following distance-time graph at points a, b, c and d.

Answer 36

d) decelerating

Question 37

In what direction does liquid pressure act?

Answer 37

All directions

Question 38

Name the force acting upwards on objects in water

Answer 38

upthrust

Question 39

When the weight of an object in water equals the upthrust on the object, what happens?

Answer 39

The object floats

Question 40

What two forces must be balanced for an object to float?

Answer 40

weight and upthrust

Question 41

What happens to liquid pressure as depth increases?

Answer 41

It increases