Physics Answers

A cyclist cycles down a hill. At the top of the hill of height 50m he reaches a speed of 50ms-1. Calculate his speed at the bottom of the hill.

We have a horizontal spring with a mass attached oscillating with a maximum displacement of

A

on either side. At which intermediate displacement(s) the kinetic energy would equal the potential

energy [10]?

The first divers used metal ‘diving bells’ to move air under the water surface.

(a) Modelling the air in bell as a hemisphere with diameter of 2.5 metres, use the following information to calculate the upthrust produced due to the water.

Ρwater= 997 kgm^-3

Volume of a sphere = 4/3𝜋r³

g = 9.81 ms^-2

(b) If the bell was fully submerged and then its suspension cable was released, what would its maximum acceleration be, given that its mass was 4500 kg?

Given that the Young modulus of steel is 210 GPa, the extension of a steel wire undergoing a stress of 300x10⁶ Pa is equal to:

A) 0.14%

B) 1.4%

C) 14%

D) 140%

The speed of a ball bearing falling through treacle:

A) Decreases with distance fallen.

B) Increases with distance fallen and reaches a maximum.

C) Is constant.

D) Reaches a maximum and then decreases.

Which of the following is not true?

A) The pressure of a fluid increases with depth.

B) The pressure of a fluid increases with the width of the container.

C) The pressure of a fluid acts in all directions.

D) The pressure of a fluid depends on its density.

What is the viscous drag acting on a sphere with a diameter of 16.2 mm falling through water at 2.3 ms^-1? Take the viscosity of the water to be 1.1 x 10^-3 Nsm^-2.

A 3.9 x 10^-4 N

B 7.7 x 10^-4 N

C 0.39 N

D 0.77 N

The volume of water (ρ = 1000 kgm^-3) that would need to be displaced to keep a person of mass 60 kg afloat on a lake on the moon Europa is:

A 0.06 m³

B 0.589 m³

C 5.89 m³

D There is not enough information in the question.

Atmospheric pressure at sea level is 101 kPa and the density of sea water is 1020 kgm^-3, therefore the total pressure 42 m underwater is:

A 420 kPa

B 521 kPa

C 4327 MPa

D 144 kPa

what is the electric flux passing through a Gaussian surface that contains 2 protons and 1 electron?