Calculating Power without distance?

• Ash Powers
In summary, the conversation discusses calculating the power of a motor needed to lift 600 N in 1 minute. The equation for power is mentioned, and it is pointed out that the distance is missing from the given information. The conversation also mentions that the question is from a GCSE revision book and has sparked an interest in physics.
Ash Powers

Homework Statement

Calculate the power of a motor that can lift 600 N in 1 Minute

The Attempt at a Solution

I've been asked to help a friends daughter with this question because I work in a Lab, unfortunately I'm a biologist working in a chemistry lab so I'm struggling![/B]

I assumed that distance was required to work out power:

power (W) = N x Distance (m)

Time (s)

Am I missing something entirely?

Hello AP, welcome to PF !

Yes, there is something missing: 600 N is a force. Work (energy) is force times distance. Power is work per time. So the calculation

Power = Force x distance / time
can't be made: the distance is missing.

Thanks very much!

This problem is in a GCSE revision book, and that is the problem word for word. At least it has got me interested in physics again, thanks for the welcome.

Strange. You can imagine it takes a bit more power to lift 600 N over 100 m in one minute than over 1 meter ...

1. How do you calculate power without knowing the distance?

Power can be calculated without knowing the distance by using the equation P = Fv, where P is power, F is force, and v is velocity. This equation is derived from the work-energy theorem, which states that the work done on an object is equal to its change in kinetic energy.

2. Can power be calculated without knowing the distance and velocity?

No, power cannot be calculated without knowing at least two of the three variables (distance, force, and velocity). This is because power is defined as the rate at which work is done, and work depends on both the force and the distance over which it is applied.

3. What units are used to measure power?

Power is typically measured in watts (W) in the International System of Units (SI). Other common units for power include horsepower (hp) and kilowatts (kW).

4. How is power related to energy?

Power and energy are closely related but are not the same. Power is the rate at which energy is transferred or work is done, while energy is the capacity to do work. In other words, power is the amount of energy used or transferred per unit of time.

5. Can power be negative?

Yes, power can be negative. This typically occurs when the direction of the force and the direction of the velocity are opposite, resulting in negative work being done on an object. For example, when a car is braking, the force is acting in the opposite direction of its motion, resulting in negative power.

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