Ben is cycling at 5 mph on a flat road and starts to accelerate to 20 mph. Force A has changed from 14 N to 37 N by the time he reaches 15 mph.
Force B changes from 27 N to 76 N when he starts to accelerate and stays at that value. Force C changes from 13 N to 17 N by the time he reaches 15 mph.

а Suggest which force is the force from the pedals. Explain your answer.

b Work out the resultant horizontal force on the bike at 15 mph and state its direction. Ben continues to pedal with the same force, but his speed stops changing when he reaches 20 mph.

с What is the resultant horizontal force on the bike at 20 mph? Explain your answer.

d How big is the combined force of friction and air resistance at 20 mph? Explain your answer.

From center station, a train departs every 30 minutes on the fast line and a train departs every 50 minutes on the state line. if two trains depart from center station at 8: 00 a.m., one on each of the two lines, what is the next time that two trains, one on each line, will depart at the same time?

Suppose that an electromagnetic wave which is linearly polarized along the x−axis is propagating in vacuum along the z−axis. the wave is incident on a conductor which is placed at z > 0 region of the space. the conductor has conductivity σ, magnetic permeability µ and electric permittivity ε. (a) find the characteristic time for the free charge density which dissipates at the conductor. (b) write the maxwell equations and derive the wave equation for a plane wave propagating in a conductor. (c) find the attenuation distance at which the incident amplitude reduces to e ^−1 of its initial value. (d) find the electric and magnetic fields inside the conductor. 8 (e) find the power loss per area of the incident electromagnetic wave at the surface of conductor.

Which changes of state do the labels represent? a: b: c: