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

Explain the difference between a real and a virtual image.

Real images are formed where two real rays cross, and they can be projected onto a screen. Whereas virtual images are seen where virtual rays intersect, they are imaginary and …

Energy generation can occur in both renewable and non-renewable ways. Part a) List three methods of non-renewable energy generation. Part b) List 2 methods of renewable energy generation. [Bonus] Part c) Why might it be beneficial to use renewable?

a) Coal/Nuclear/(Natural) gas.b) Any two from Wind/Hydroelectricity/Solar/Geothermal or any other equally valid form of renewable energy generation.[Bonus] c) Fossil Fuel emissions can release gases into our atmosphere that …

State Newton's 3 Laws in words and/or mathematically

1st Law - An object will remain at rest or continue at constant velocity unless acted on by an unbalanced force
2nd Law - F=ma (for a constant mass body) …

Alice and Bob are sat on a seesaw. The seesaw is in static equilibrium. Alice weighs 500N and is sat 0.5m to the left of the pivot. If Bob weighs 800N, how far from the pivot on the right is he sat? What happens if Bob moves closer to the pivot?

First of all draw a diagramIf the seesaw is in static equilibrium this means:There is no net force on the seesawThere is no net moment on the seesawAs a result …

I never know where to start where I get a calculation question given many values, what should I do? (e.g: finding how much energy is needed for all the ice in a glass of water to melt after the ice is dropped into warm water)

Firstly, you should always list down the values that were given to you in the question so that you know exactly what you already know, and then by looking at …

A bowling ball is thrown into the alley, having velocity of 3 ms^-1 at the start of the bowling alley. It decelerates at a constant rate, before hitting the skittles at 2 ms^-1 after 4 s A) calculate the acceleration of the ball.

A) acceleration (m/s2) = change in velocity (m/s) / time (s)
A) -1.0 ms^-1 / 4 s = -0.25 ms^-2
B) Calculate the displacement the ball travelled before …

What is the resistance (in Ohms) of two 20 Ohm resisters in parallel?

1/20 + 1/20 = 1/R2/20 = 1/R1/10 = 1/RR = 10
Now, answer for a 20 Ohm and a 10 Ohm resister in parallel?1/20 + 1/10 = 1/R3/20 = 1/RR …

Jane drops a football from the roof onto the ground below. The ball weighs 0.8kg and the distance the ball falls is 5m. Assuming there are no external forces acting on the ball, what speed will the ball be travelling at just before it hits the ground?

As the ball falls from a height to the floor, the gravitational potential energy stored in the ball will be converted to kinetic energy.The gravitational potential energy of the ball …

When going around a roundabout, why do I feel a force pulling me outwards?

The force pulling you outwards is what is called fictional force. Actually, there is a force pulling the car inwards and since Newton's Laws mean that you want to keep …

What is the difference between alpha and gamma radiation?

Alpha radiation is a type of radiaiton which has a high ionisation and low penetration. This means it can ionise objects very easily (so can be more damaging to humans) …

Draw a graph depicting a skydivers speed against time when jumping from a plane, until he deploys his parachute, explaining the logic of your answer through the forces applicable to the body.

Upon jumping from the plane, the diver experiences three forces; a downward force from his weight; opposed by a lift force (equal to the weight of the air he displaces); …

A person swims from a depth of 0.5m to 1.7m below the surface of the sea. Denisty Sea Water = 1030 kg/m^3. g=Gravitational Field Strength = 9.8 N/kg. Calculate the change in pressure on the swimmer and give the unit.

Use equation: Pressure = density x depth in the fluid x gravitational field strength. We know the in increase in pressure will be the difference between the Final Pressure (at …

Explain what the terminal velocity of an object is.

The terminal velocity of an object is the highest velocity it can reach when falling through a defined medium, usually air in practice. This constant velocity is achieved when the …