Work in scientific terms is defined as applying force to an object that causes it to ___ in the direction of that force.

Move

True or False: If a force is applied to an object but it does not move, then the work done on that object is considered to be ___ zero.

True

Work done is defined as the product of ___ and ___.

Force and displacement

True or False: The unit of work is Newton meter (Nm) or joule (J).

True

When lifting an object, the work done is calculated using W = F × S, but if the force is applied at an angle θ, the formula adjusts to ___ = F × d × cos(θ).

Work

A porter lifts luggage weighing 15 kg to a height of 1.5 m. Calculate the work done, including the gravitational force (g = 10 m/s²).

Work Done = Force × Displacement

• Mass of the luggage, m = 15 kg
• Height lifted, h = 1.5 m
• Gravitational acceleration, g = 10 m/s²

The force required to lift the luggage is equal to its weight:

Force = m × g = 15 × 10 = 150 N

Work Done = 150 × 1.5 = 225 J

225 Joules (J)

Work is considered positive when __________________________.

The displacement of the object is along the direction of the force applied

True or False: If an object moves in a direction perpendicular to the applied force, work done is considered positive.

False. Work done is zero when the displacement is perpendicular to the force, regardless of the force acting.

Kinetic energy is dependent on the mass of the object and its ___?

Velocity

True or False: Gravitational potential energy is the energy associated with an object's motion.

False. Gravitational potential energy is related to an object's position relative to the ground.

The potential energy (Ep) of an object lifted to a height h is given by the formula ___ where m is the mass and g is the acceleration due to gravity.

Ep = mgh

True or False: The work done by gravity when lifting an object depends on the path taken to move the object.

False; the work done by gravity depends only on the difference in vertical heights between the initial and final positions of the object.

An object has a potential energy of 480 J and a mass of 12 kg. What is its height above the ground?

The height of the object can be found using the formula E = mgh. Rearranging gives h = E / (mg). Substituting the values, h = 480 J / (12 kg * 10 m/s²) = 4 m.

In the context of a freely falling object, potential energy is converted into ___ as the object descends.

Kinetic energy

True or False: The law of conservation of energy states that energy can be created but not destroyed.

False. The law states that energy cannot be created or destroyed; it can only be transformed from one form to another.

The total mechanical energy of a pendulum remains constant due to the law of ___ and ___ energy.

Conservation and transformation

Power is defined as the rate of doing work, calculated using the formula Power = ___ / ___.