AP physics question please?

Question

1) A lightbulb with a resistance of 50.0 ohms is used in a circuit with a 9.0-volt battery. What is the current through the bulb?

2) An object with uniform acceleration A, starting from rest, will reach a speed of V in time T according to the formula V= at. What is the acceleration of a bicyclist who accelerates from rest to 7 m/s in 4 s?

3) How long will it take a scooter accelerating at 0.400 m/s² to go from rest to a speed of 4.00 m/s?

4) The pressure on a surface is equal to the force divided by the area: P= F/A. A53-kg woman exerts a force (weight) of 520 Newtons. If the pressure exerted on the floor is 32,500, N/m², what is the area of the soles of her shoes?

im desperate for help, i just don't really understand these...

Answer 1

1)

V=IR

Current = 9/50=0.18 amps

2)

a = V/t

Acceleration = 7/4 = 1.75 m/s^2

3)

t = V/a

time = 4/0.4 = 10 secs

4)

A = F/P

area = 520/32500 = 0.016 m^2