Physics Quiz on Motion and Forces

Newton’s third law of motion explains the two forces namely ‘action and reaction’ coming into action when the two bodies are in contact with each other. These two forces:

• Always act on the same body.

• Always equal in magnitude and opposite in direction.

• Have same magnitude and direction.

• Acts on either body at normal to each other.

In a rocket, a large volume of gases produced by the combustion of fuel is allowed to escape through its tail nozzle in the downward direction with the tremendous speed and makes the rocket to move upward. Which one of the following laws is followed in this take off of the rocket?

• Law of inertia

• Newton’s third law of motion

• Newton’s law of gravitation

• Newton’s second law of motion

According to Newton’s first law of motion, an object in motion will

• Slow down when moving down a hill

• Stay in motion unless acted upon by an outside force.

• Always move sideways when acted upon by an outside force.

• Stay in motion when it is acted upon by an outside force.

Kinga pushes a box of mass 30 kg with a force of 60 N. What is the acceleration of the box?

• 1 𝑚𝑠−2

• 0 𝑚𝑠−2

• 2 𝑚𝑠−2

• 0.5 𝑚𝑠−2

Scalar quantities have

• Magnitude only

• Direction only

• Magnitude and direction

• None of the above

The density of liquid is measured by

• Manometer

• Thermometer

• Barometer

• Hydrometer

A body weighs 450 gf in air and 310 gf when completely immersed in water. The up thrust on the body is

• 760 gf

• 310 gf

• 140 gf

• 130 gf

The upthrust acting on a body increases with increase in the _________ of the liquid in which it is submerged.

• Volume

• Mass

• Density

• Gravity

The pressure at the bottom of a glass of water is P (Density of water = 1000 kg𝑚−3). If the water is replaced by kerosene (Density = 817.5 kg𝑚−3) then the pressure at the bottom will be

• Equal to P

• Less than P

• More than P

• Zero

The upward force of liquid acting on a submerged object is

• Friction force

• Air resistance

• Buoyant force

• Resultant force