Physics Homework [Forces 2]

Question 1

If two forces on an object act in opposite directions, describe how the size of the resultant force is calculated.

Answer 1

By subtracting the forces from each other.

Question 2

If an object is travelling at a constant velocity, is there a resultant force acting on it?

Answer 2

No

Question 3

Define vector quantity.

Answer 3

Something measured that has both a magnitude and direction.

Question 4

State the standard units for work done.

Answer 4

Joules (J)

Question 5

Define scalar quantity.

Answer 5

Something measured that only has a magnitude.

Question 6

Define non-contact force.

Answer 6

When two interacting objects do not have to physically touch to interact.

Question 7

Define resultant force.

Answer 7

The single force that has the same effect as all the individual forces on an object acting together.

Question 8

Describe how a resultant force is calculated.

Answer 8

By adding all the individual forces on an object as vectors.

Question 9

State Newton’s third law.

Answer 9

When two objects interact, the forces exerted on one another are equal in size and opposite and direction.

Question 10

Give examples of non-contact forces.

Answer 10

Gravitational force (Weight), electrostatic force, magnetic force.

Question 11

Give three examples of contact forces.

Answer 11

Friction, air resistance, tension, normal contact force.

Question 12

If the forces on an object are balanced, give the resultant force.

Answer 12

0 N

Question 13

State Newton’s first law.

Answer 13

When the resultant force acting on an object is zero, there is no change to the object’s motion.

Question 14

Define inertia.

Answer 14

The tendency of objects to continue in their state of rest or uniform motion.

Question 15

When a force arises between two objects, state which of the two interacting objects experiences this force.

Answer 15

Both of the objects experience the force, equal in magnitude, but opposite in direction.

Question 16

Define the centre of mass of an object.

Answer 16

The imaginary point that the force of the object’s weight seems to act through.

Question 17

State Newton’s second law.

Answer 17

When a resultant force acts on an object, the object accelerates.

Question 18

State the standard units for mass.

Answer 18

Kilograms (kg)

Question 19

If an object is changing velocity, is there a resultant force acting on it?

Answer 19

Yes