Which type of force acts between two surfaces that are in contact and opposes relative motion?

Frictional force opposes the relative motion between two surfaces in contact.

The SI unit of force is:

The SI unit of force is the Newton (N), named after Sir Isaac Newton.

An object of mass 5 kg is accelerated at 2 m/s². What is the net force acting on it?

Force (F) = mass (m) × acceleration (a) = 5 kg × 2 m/s² = 10 N.

Which law of motion states that 'For every action, there is an equal and opposite reaction'?

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction.

Kinetic energy of an object depends on its:

Kinetic energy (KE) = ½ × mass × velocity².

The energy stored in a stretched spring is an example of:

A stretched spring stores elastic potential energy.

Which of the following is a unit of power?

Power is measured in watts (W), where 1 W = 1 J/s.

A machine does 500 J of work in 10 seconds. Its power is:

Power = Work / Time = 500 J / 10 s = 50 W.

Heat transfer through a solid material without the movement of the material itself is called:

Conduction is the transfer of heat through a solid material.

Which of the following is the best conductor of heat among these?

Metals like iron are good conductors of heat.

The temperature at which the kinetic energy of particles theoretically becomes zero is:

Absolute zero is 0 K or -273.15°C, where particle motion theoretically stops.

Work done on an object is zero if:

Work is zero if there is no force, no displacement, or the force is perpendicular to displacement.

A ball is thrown upward. At the highest point, its:

At the highest point, velocity is zero, so kinetic energy is zero and potential energy is maximum.

Which law of thermodynamics states that energy cannot be created or destroyed?

The First Law of Thermodynamics states that energy is conserved.

The phenomenon of heat transfer in fluids due to the movement of heated particles is:

Convection is heat transfer in fluids due to particle movement.

An iron rod is heated at one end. The other end becomes hot after some time. This is due to:

Heat is conducted through the iron rod from the hot end to the cooler end.

A body of mass 2 kg has a velocity of 3 m/s. Its kinetic energy is:

Kinetic energy (KE) = ½ × 2 kg × (3 m/s)² = 9 J.

Which type of energy is converted when a battery powers a torch?

A battery converts chemical energy to electrical energy, which is then converted to light energy in the torch.

The ability to do work is called:

Energy is the capacity to do work.

Which of the following is NOT a unit of heat energy?

Kelvin is a unit of temperature, not energy.

The specific heat capacity of a substance is the amount of heat required to:

Specific heat capacity is defined as the heat required to raise the temperature of 1 kg of a substance by 1°C.

A cool object placed in a warm room eventually becomes warm. This is mainly due to:

Heat transfer occurs through conduction, convection, and radiation.

Which of these is a vector quantity?

Force has both magnitude and direction, making it a vector quantity.

The acceleration due to gravity (g) on Earth’s surface is approximately:

g is approximately 9.8 m/s² and also 9.8 N/kg.

A person lifts a 10 kg box to a height of 2 m. Work done against gravity is:

Work (W) = mass (m) × gravity (g) × height (h) = 10 kg × 9.8 m/s² × 2 m = 196 J.

Which law of motion explains why a passenger leans forward when a bus suddenly stops?

Inertia causes the passenger to continue moving forward when the bus stops suddenly.

The rate of doing work is called:

Power is the rate at which work is done.

When you rub your hands together, they become warm. This is because:

Friction converts kinetic energy into heat energy.

In which process is heat transferred without any medium?

Radiation is the transfer of heat through electromagnetic waves and does not require a medium.

The total mechanical energy of a freely falling object (ignoring air resistance):

The total mechanical energy (kinetic + potential) is conserved in free fall.