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A kettle has a 55% energy efficiency. The input energy for the kettle is 378,000 J per boil. Calculate the amount of energy dissipated in 5 boils.

Energy used for one boil = (3.78 x 10⁵/ 100) x 55Energy used for one boil = 2.079 x 10⁵J Energy lost per boil = 3.78 x 10⁵-2.079 x 10⁵Energy lost per boil = ...

Answered by Ryan A. • Physics tutor

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Person A, weighing 35 kg, is sitting 10m away from a seesaw pivot. Person B, weighing 50 kg, it sitting at the other end, at a distance d. Calculate d, in order for the seesaw not to topple over. (g=10m/s^2)

Force@A: F_A = m_A x g = 35 x 10 = 350NAnticlockwise moment: M_A = F_Ax d_A= 350 x 10 = 3500NmForce @B: F_B=m_b x g = 50 x 10 = 500NC...

Answered by Antonia A. • Physics tutor

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How does refraction work?

The fastest light can travel is when it is in a vacuum, where it travels at 3x10^8 metres per second.

However, when light travels through another substance or material (anothe...

Answered by Conor P. • Physics tutor

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How do I use equations of motion ('suvat') to find a missing quantity?

First, be familiar with the equations of motion:s = displacementu = initial velocityv = final velocitya = acceleration (constant)t = time
v = u + ats = ((u+v)t)/2s = ut + (at^2)/2v^2 = u^2 + 2as

Answered by Jessica H. • Physics tutor

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why does applying the brakes of a car cause the temperature of the breaks to increase?

The increase in heat is caused by friction between the brakes and the wheels. This work done between the brakes and the wheels, causes a decrease in kinetic energy ...

Answered by Hugo H. • Physics tutor

11875 Views