Newtonian Mechanics

Question 1

In relation to Newtonian mechanics (true or false):

1 N is the force required to give a mass of 1 kg an acceleration of 9.81 m/s2

Answer 1

False. 1 N gives a mass of 1 kg an acceleration of 1 m/s2.

Question 2

In relation to Newtonian mechanics (true or false):

Momentum is inversely proportional to mass

Answer 2

False. Momentum is proportional to mass.

Question 2

In relation to Newtonian mechanics (true or false):

Inertia increases with the mass of an object

Answer 2

True. The tendency of an object to resist changes in its state of motion is dependent upon mass. The greater the mass of an object, the more inertia it has – the more tendency it has to resist changes in its state of motion.

Question 3

In relation to Newtonian mechanics (true or false):

The acceleration of an object is inversely proportional to the force acting upon it

Answer 3

False. Acceleration is directly proportional to the force acting upon it.

Question 3

If a mass (m) is acted on by net force (F) (true or false):

The momentum of the mass would remain constant

Answer 3

False. Momentum is the product of mass and velocity; the mass will accelerate, its velocity will increase and so too will its momentum.

Question 4

If a mass (m) is acted on by net force (F) (true or false):

The velocity of the mass would be inversely proportional to m

Answer 4

False. The acceleration, not the velocity, will be inversely proportional to m (force = mass × acceleration).

Question 5

If a mass (m) is acted on by net force (F) (true or false):

If m is doubled then F must also be doubled to achieve the same acceleration

Answer 5

True. Force = mass × acceleration.

Question 6

If a mass (m) is acted on by net force (F) (true or false):

The mass would not necessarily move

Answer 6

False. The mass would not move if the net force is zero. Take the example of a book on a table acted on by the force of gravity.

Question 7

If a mass (m) is acted on by net force (F) (true or false):

The velocity of the mass would remain unchanged

Answer 7

False. The mass will accelerate therefore the velocity of the mass will increase.

Question 8

In relation to Newtonian mechanics (true or false):

Mass and weight are equivalent

Answer 8

False. Weight describes the force of gravity on a mass; a mass of 1 kg on the surface of the Earth weighs 9.81 N.

Question 9

In relation to Newtonian mechanics (true or false):

Acceleration is equal to the product of the mass of an object and the magnitude of the external force applied

Answer 9

False. Acceleration = Force applied/mass.

Question 10

In relation to Newtonian mechanics (true or false):

Momentum varies directly with the velocity of an object

Answer 10

True. Momentum is the product of mass and velocity.

Question 11

In relation to Newtonian mechanics (true or false):

Weight is expressed in newtons

Answer 11

True. Force is expressed in newtons, and weight is the force of gravity acting on a mass.

Question 12

In relation to Newtonian mechanics (true or false):

A stationary object has both momentum and inertia

Answer 12

False. A stationary object has inertia but not momentum.