Other Physics Answers

Which of the following is the correct unit for momentum?

A) kg s^-1

B) kg m s^-1

C) kg m s^-2

D) kg m^-1 s^-1

Which unit is not used to measure pressure?

A) pound-force per square inch (psi)

B) kilogram per metre cubed

C) millimetre of mercury

D) newton per square metre

Using the following equations for force, work done, power, current and potential difference (or otherwise) give the following derived units in terms of base units. Show all of your working.

F=ma, W=Fd, P=ΔW/Δt', I=ΔQ/tΔ, V=W/Q

a. Joules

b. Watts

c. Volts

if the period of rotation is 3 seconds what is its angular frequency

A 15 A current flows in a device that has a resistance of

0.15Ω. Compute the rate of heat production by the device.

The heating element in a hair dryer is rated at 5kW and

220V . How much current does it draw?

An electric toaster has a resistance of 12 Ω. What current will it draw

from a 120 V supply?

What is the potential difference across a hand-held fan that has a

resistance of 120 Ω and a current of 50 mA flowing through it?

What is the resistance in a circuit if a potential difference of 110 V

causes a current of 10 A?

Calculate the current an electric clothes dryer draws when it is

connected to a 230 V source and has a resistance of 9.2 Ω