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If a student uses an electric kettle connected to a 230V mains power supply, with a heating power of 1.8kW. Assuming negligable losses, answer the following: a) find the current in the kettle b) find the total energy transferred in 2 minutes of operation

a) The governing equation here is Power = current x voltage or P=IV. using this formula, 1,800 = I x 230 => I=1800/230 = 7.83 A (3sf) b) as watts is equal to joules/seconds, we can find the energy in j...

Answered by Chris P. • Physics tutor

19630 Views

What is the maximum length a bungee rope with a spring constant of 100 Nm−1 can be for an 80kg man to be able to jump from 100m above a river without touching the water?

The key to solving this problem is realising that gravitational potential energy and elastic potential energy need to be equated. The gravitational potential energy of an object of mass m at height h abov...

Answered by Samuel J. • Physics tutor

12773 Views

The friction coefficient of Formula 1 car tyres are around 1.7 in dry weather. Assuming sufficient power from the engine, calculate the theoretical best 0-100 km/h acceleration time in seconds. (neglect downforce, g=9.81m/s^2)

We have to appreciate the assumptions we are working with. The problem states that power is available infinitely, therefore the maximum acceleration influencing factor is the tire grip. It is reached when...

Answered by Balazs V. • Physics tutor

18353 Views

Why do objects reach terminal velocity?

The force of gravity acts on an object, causing it to accelerate towards the earth. As it’s velocity increases the drag force (friction) exerted on it by the air increases. When the two forces on the obje...

Answered by Aylin L. • Physics tutor

14464 Views

A pendulum of mass m is released from height h with a speed v at the bottom of its swing. a) What is the gravitational potential energy at height h and the kinetic energy at the bottom of its swing? b) Use conservation of energy to define the speed v.

a) To begin with we will calculate the gravitational potential energy at height, h. This is the result of the mass, m, being lifted through earth's gravitational pull, (approximated as g = 9.81 m/s at the...

Answered by Rachel H. • Physics tutor

6240 Views