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Why is the car moving if the unbalanced force is zero?

This is a great example of where physics and our gut feelings about physics don't match up. This is a very common conceptional difficulty students have and is often jumped on by examiners. The best way to th...
CD
Answered by Connor D. • Physics tutor
19506 Views

An electric heater has a power of 1000W. It is connected to mains electricity (230V). The heater is equipped with an Earth wire. a) Calculate the current in the heater. b) Explain the role of the earth wire as a safety feature.

a) Use the equation P=IV where P is power in W, I is Current in Amps and V is voltage in volts. Rearrange to give I=P/V I=1000/230 = 4.34 A b) This is a wire connected to the metal casing of an electrical ap...
KS
Answered by Katie S. • Physics tutor
16343 Views

Circut is arranged in a loop, with resistor (5 ohm), power source(2V), resistor (3 ohm), and another power source (3V) connected subsequently. What is the voltage on 5ohm resistor?

The questions is constructed to show, that the order of devices do not affect the currents or voltages. 5ohm / ( 3 + 5)ohm = x/ 2V +5V x = 35/8 V = 4 3/8V
AW
Answered by Anna W. • Physics tutor
2649 Views

a bat emits sound waves with a range of wavelengths. Some of the sound waves will be diffracted by the insect. Complete the following sentences to explain why. [2 marks] Diffraction is caused by the sound waves _______________________________________

spreading out
RT
Answered by Ralph T. • Physics tutor
3912 Views

A 950 kg car accelerates from 0 to 33 m/s in 11 seconds. a) Calculate the acceleration of the car b) Calculate the force needed to produce this acceleration c) The car claims a top speed of 110 miles/hr. Explain why there must be a top speed for any car

a) a=v-u/t = 33/1 = 3 b) F = ma = 950x3 = 2850 c) Friction and air resistance increases with speed, till frictional = max forward force, then force/acceleration is zero
RB
Answered by Raina B. • Physics tutor
11399 Views