**Explanation:**

It is known that it does not matter at what angle the force has been applied on an object because they all are acting perpendicular to the axis.

And, expression for torque from each force is as follows.

where, F = magnitude of force

r = distance from the center

Total torque will be calculated as follows.

Nm

= 3.9 Nm

Therefore, we can conclude that** the magnitude of the net torque on the wheel about the axle through the center of the object is 3.9 Nm.**

**Answer:**

remains the same, but the apparent brightness is decreased by a factor of four.

**Explanation:**

A star is a giant astronomical or celestial object that is comprised of a luminous sphere of plasma, binded together by its own gravitational force.

It is typically made up of two (2) main hot gas, Hydrogen (H) and Helium (He).

The luminosity of a star refers to the total amount of light radiated by the star per second and it is measured in watts (w).

The apparent brightness of a star is a measure of the rate at which radiated energy from a star reaches an observer on Earth per square meter per second.

The apparent brightness of a star is measured in watts per square meter.

If the distance between us (humans) and a star is doubled, with everything else remaining the same, the luminosity remains the same, but the apparent brightness is decreased by a factor of four (4).

Some of the examples of stars are;

- Canopus.

- Sun (closest to the Earth)

- Betelgeuse.

- Antares.

- Vega.

2 wheels force is put on the back gear to push a larger gear on front . when pedalling on flat force should be applied on middle to smaller size. However when bike reached a terminal force it rider will move to smaller gear and go faster. If bike is going down hill the force of gravity will mean rider can manage the smallest gear as in fastest speed as Force = Mass × Velocity and the impact of gravity means less force is required as the weight of the bike and rider However the opposite it through for uphill as the rider is going against gravity ..weight and gravity will mean the rider will need to go to the larger gear the slower speed.

There are other factors as in wind and slip stream and type of pedals to maximise the force.

**Answer:**

**a)P = 78.21 KN**

**b)L=128.285 mm**

**Explanation:**

Given that

E= 116 GPa

σ = 259 MPa

a)

A= 302 mm²

Lets take load P can applied without plastic deformation

We know that

P = σ A

P = 259 x 302 N

P = 78218 N

**P = 78.21 KN**

b)

Lo= 128 mm

Lets take final length = L

Change in length ΔL

Strain ε = ΔL/L

ε = σ/E

By putting the values

ΔL=0.285 mm

The final length L

L = ΔL + Lo

L = 0.285 + 128

**L=128.285 mm**