Gcse Physics Question Help

GCSE physics question help?

a box weighs 2000 N. it is accelerated uniformly over a horizontal surface at a rate of 8.00m/s2. the opposing force of friction between the box and the surface is 27.4 N.

a) how much force is exerted horizontally on the box?
b) how much force would be required to LIFT the box upward with an acceleration of 8.00 m/s2?

GCSE Physics question (Help)?

Here, you just need to recall the formula that connects wavelength, frequency and velocity.

Velocity (m/s) = frequency (Hz) * wavelength (m)
So

frequency = velocity / wavelength

frequency = 300,000,000 * 0.0003 = 9 * 10^4 Hz = 90,000 Hz = 90 kHz

Help with GCSE physics question?

transformers will only convert AC TO AC ... a battery is DC


you need to use a better trick to convert to 2.4 volts

if you know about diodes i can show you a trick...


when you connect 12 V to a silicon doide it will only create a voltage drop of 0.7 volts

so if you want to make 2.4 volts you need about 4 diodes



12 volts NEG --- resister -------|<----D2-----D3-----D4----12 v POSITIVE
______________________D1


see the line in the diagram thats the same line that appears on a diods case.. thats how ou connect it...

now the resistor has to be chosen so that it creates a current of less than the value the diodes can handle


since the diodes will have 2.8 volts across them

from 12 thats 9.2V left on the resistor


so a 9.2 ohm resister will make 1 amp

I dont know what the amperage of the motor is but thats pretty high for most 2.4 volt motors

you may need something in the range of 100 mA


or 0.1 amp which is 92 ohm resister..

if you connect the negative of the MOTOR to the point between the resister and the bar of the first diode and the POSITIVE OF THE MOTOR to the point between the PLUS on the battery and the last diode

that circuit will make your motor work


you need 0.2 to 0.5 amp rectifying diodes and 0.2 amp 92 ohm resister for the 100 mA version

or 1.5 to 2 Amp 9.2 ohm resister and 1.5 to 2 amp rectifying diodes for the 9.2 ohm resister 1 amp circuit ...

the reason you use higher values is to be SAFE...


these circuits will work but have a science teacher help you or a parent who knows electricity ok

IF YOU CONNECT THE BATTERY tot he diodes the OTHER WAY the voltage the motor will see is 12 volts so you will burn out the motor please be careful...

you can ADD another diode to make it fool proof that will make it see 0 VOLTS or the proper amount



12 V negative -----D5------resister --.A --- D1-----D2-----D3-----D4--B---- pos 12 volts


point A and point B are the points where the motor will see 2.8 volts DC

GCSE Physics question help?

so im studying GCSE Additional science on aqa. im doing a past paper and i don't understand the question. I've checked the mark scheme and it doesn't offer an explanation. i was wondering if anyone could help me work out how the answer was reached.

5) this diagram shows a motorbike of mass 300kg being ridden along a straight road.
*DIAGRAM SHOWN OF SOMEONE ON A BIKE*

the rider sees a traffic queue up ahead. he applies the brakes and reduces the speed of the motorbike from 18m/s to 3m/s.

use this equation to calculate the kinetic energy lost by the motorbike.
kinetic energy = 0.5 x mass x speed^2.

the answer should be 47250J. but how is this reached?

5b) also, how much work is done on the motor bike by the braking force?

Gcse physics questions help!!!!!?

1) Give two reasons why most manufacturers of double glazed windows are unlikely to ise an air gap any larger than 20mm

2) explain how the Fraunhofer lines are formed and how they tell us about the composition of the sun

HELP GCSE Physics Questions?

6) Bob has an electric lawn mower which transfers 5kWh of energy. Each kWh of energy costs 10p. Calculate the total cost of running his lawn mower. ________________________________________...

7) Ingrid’s washing machine has a power of 2kW. She uses it for 2 hours. Each kWh costs her 5p. First calculate the energy transferred by the washing machine. ________________________________________...
Now calculate the total cost of running the washing machine. ________________________________________...

8) Julie uses her hair dryer for 30 minutes. The hair dryer has a power of 500W. Calculate the cost of Julie drying her hair if each kWh costs 8p. ________________________________________...

GCSE physics question?

A small notebook computer has a power rating of 40W.
The computer is connected to the mains supply through a step-down transformer. The mains supply is alternating current.

The step-down transformer has:
- 2400 turns on the primary coil
- 200 turns on the secondary coil
- a primary voltage of 230V.

Calculate the voltage of output of the secondary coil.

This equation will help you to work it out:
Primary voltage / secondary voltage = Number of turns on primary coil / number of turns on secondary coil

I've tried working this out and when I looked at the answer, I got the answer wrong, but I don't understand where I'm going wrong, so I'm wondering if someone else could tell me how you work it out step by step. Thanks :)

GCSE Physics Question?

The energy value of gas used in a home is measured in KWH. The home owner has a prepayment meter and pays £30 into his account. With a prepayment meter, gas cost 15p per KWH. Use the below equation to calculate the total number of hours that the gas boiler would operate for £30.
Energy Transferred = power x time
Total costs = number of kilowatt hours x cost per kilowat-hour

GCSE Physics question?

im doing the physics exam 2moro and its confusing as f*uck. but i luckily understand this question.

(0.5*300*18^2)-(0.5*300*3^2)=47250

bacially workout the kinetic energy for when he was going at 18m/s and 3m/s and get the difference.

could u check my physics question and see if u can answer it plz.