Power

What is the definition of power in physics?

• The rate at which work is performed

• The total energy in a system

• The force applied to an object

• The distance an object moves

Answer explanation

In physics, power is defined as the rate at which work is performed. This means it measures how quickly energy is transferred or converted, making 'the rate at which work is performed' the correct choice.

What is the formula for calculating work?

• W = F × d

• W = P × t

• W = m × a

• W = V × I

Answer explanation

The correct formula for calculating work (W) is W = F × d, where F is the force applied and d is the distance moved in the direction of the force. This formula directly relates to the definition of work in physics.

In what unit is work measured?

• Joules (J)

• Newtons (N)

• Watts (W)

• Meters (m)

Answer explanation

Work is measured in Joules (J), which quantifies energy transfer. Other options like Newtons (N) measure force, Watts (W) measure power, and Meters (m) measure distance, making Joules the correct unit for work.

What is the unit of power?

• Watts (W)

• Joules (J)

• Newtons (N)

• Meters per second (m/s)

Answer explanation

The unit of power is Watts (W), which measures the rate of energy transfer. Joules (J) measure energy, Newtons (N) measure force, and meters per second (m/s) measure speed, making Watts the correct choice.

How is force measured?

• Newtons (N)

• Joules (J)

• Watts (W)

• Kilograms (kg)

Answer explanation

Force is measured in Newtons (N), which is the standard unit in the International System of Units (SI). Other options like Joules, Watts, and Kilograms measure energy, power, and mass, respectively, not force.

What is the formula for calculating work (W) when force (F) and distance (d) are given?

• W = F × d

• W = F + d

• W = F / d

• W = F - d

Answer explanation

The correct formula for calculating work (W) is W = F × d, where W is work, F is force, and d is distance. This formula shows that work is the product of the force applied and the distance over which it is applied.

If Moby lifts a dumbbell in 10 seconds, producing 2 watts of power, how much power is produced if he lifts it in 5 seconds?

• 4 watts

• 1 watt

• 2 watts

• 10 watts

Answer explanation

Power is calculated as work done over time. If Moby lifts the dumbbell in half the time (5 seconds), the power doubles. Thus, 2 watts in 10 seconds becomes 4 watts in 5 seconds.

Why is understanding the concepts of power, work, and force important?

• To grasp how energy functions in our world

• To calculate the speed of light

• To measure temperature changes

• To determine the color of objects

Answer explanation

Understanding power, work, and force is crucial to grasp how energy functions in our world, as these concepts are fundamental to physics and help explain how energy is transferred and transformed in various systems.

What unit is used to measure power?

• Watts

• Joules

• Newtons

• Meters

Answer explanation

Power is measured in Watts, which quantifies the rate of energy transfer. Joules measure energy, Newtons measure force, and Meters measure distance, making Watts the correct unit for power.

What is the formula for calculating work done?

• Work = Power x Time

• Work = Velocity x Time

• Work = Mass x Acceleration

• Work = Force x Distance

Answer explanation

The correct formula for calculating work done is Work = Force x Distance. This means that work is the product of the force applied to an object and the distance over which that force is applied.