Physics Questions & Answers - Physics Doubts, Problems, Homework Solutions

Explain why the stability of a car can be improved by widening the wheel base and lowering the centre of gravity.

A car will topple over when it is tilted so far that the line of action from the centre of gravity falls outside of the wheel base, causing a resultant …

describe the process of nuclear fission

a neutron is absorbed by a big nucleusthe nucleus then splits into 2 smaller nucleithis releases energy and more neutrons

Why do you weigh less on the Moon than on Earth?

Weight is the product of an object's mass and the dominant gravitational field that it feels. On Earth, objects feel a gravitational acceleration which is dependent on the mass of …

A coil is connected to a voltmeter. A bar magnet, initially held above the coil, is left to fall into the coil. Explain why the voltmeter shows a reading. How will the reading of the voltmeter be affected if the magnet is dropped from a greater height?

As the bar magnet enters and exits the coil, there is a change in magnetic flux linkage through the coil. According to Faraday's law, an EMF is induced across the …

A roller coaster car starts stationary at the top of a downwards slope. At the bottom of the slope, it has a speed of 30m/s. Use the conservation of energy to find the vertical height of the slope. (Use g=10 m/s^2)

From the conservation of energy, we know that the change in gravitational potential energy (GPE) is equal to the change in kinetic energy (KE). GPE=mgh and KE=(1/2)mv^2. At the top …

Why does a wire get hot when current flows through it?

Current is defined as the flow of electrons. This flow is caused by the electrons within the wire being pulled by electric field. As the electrons travel through the wire …

How do you rearrange equations at Physics GCSE ?

Take the equation W=Fs. We want to make one thing the subject of the equation by clearing away all the stuff we don’t want on that side of the …

What is meant by 'dissipated energy'?

In a system, we can transfer energy from an energy store into one or more useful forms of energy, however this process is not 100% efficient and some energy is …

How do Transformers work?

Transformers are two coils of wire, coiled around each side of an iron core (primary and secondary). The primary coil has a potential difference supplied to it that drives the …

explain how a parachutist reaches a constant speed using the concept of terminal velocity.

1 - parachutist is in plane, they are stationary so according to Newton's first law the forces acting on them (weight downwards and reactionary force upwards) are equal. 2 - …

How does current travel in a parallel circuit?

The current is split at electrical junctions. The total current entering a junction is equal to the total current exiting a junction. More current passes through the path with least …

A satellite is in orbit of the Earth, and moves at a constant orbital speed of 3055.5m/s. If it is at an altitude of 35786km, calculate the time period for a complete cycle, giving your answer in hours. Answer should be given in in 3 significant figures.

Orbital Speed = [2Π(Orbital Radius)]/Time Period
3055.5m/s = 10999.8km/h
therefore:
10999.8km/h = [2Π(35786km)]/TT = [2Π(35786km)]/(10999.8km/h)T = 20.4 hours

If Max weighed 17.2 N on Ceres (gravitational field strength of 0.27 N/kg), then what would she weigh on Earth. Give your answer to 3 s.f. and state your units.

For this question you only need to know one equation, however, what is key is to be able to understand what the question is asking for and how to go …

What are the two types of waves and what are some of their uses/sources?

Transverse:Radio signalsElectromagnetic radiationTVPhone serviceOcean wavesLongitudinal:Seismic wavesSound wavesect.

Discuss a use and a harmful effect for three parts of the electromagnetic spectrum

Gamma rays can be used to sterilise medical instruments, however, they can cause cancer.Ultraviolet waves can be used for security on bank notes, however, they can cause sunburn and blindness.Microwaves …

There is an oil tank that has a rectangular base of dimensions 2.4 m by 1.5 m. The tank is filled with oil of density 850 kg / m3 to a depth of 1.5 m. What is the mass of the oil?

2.41.51.5*850=4590kg

Why are some electromagnetic waves harmful to humans?

Electromagnetic (EM) waves form the electromagnetic spectrum with a range of wavelengths. EM waves that have wavelengths shorter than those of visible light include ultraviolet light, X rays and gamma …

What name is given to the phenomena which results in longer wavelengths of light being observed from distant galaxies and why does this occur?

Red shift; this phenomena occurs as a result of the distant galaxies moving away from the Earth and all the wavelengths of electro-magnetic radiation being emitted are 'stretched' towards to …

Explain the role of the moderator in a fission reaction.

slows neutrons/reduces KE of neutrons so that neutrons can be absorbed by the U-235 nucleus to cause fission to release kinetic energy. (nuclear reactor and energy)

What is the density of a rock (mass 75g) submerged in water which displaced by a volume of 37.5cm^3? SI units

75g = 0.075kg/ 37.5cm3 = (37.5 divided by 1003) m3 = 3.7510-5m3/ density = mass divided by volume/ 0.075 divided by …