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Two cars are crash tested. Car A has a crumple zone, B doesn't. Both cars have mass 1500kg and a driver of mass 80kg and crash at 20m/s. Cars A and B take 0.8 and 0.2 seconds to stop respectively. Using this information, are crumple zones a necessity? (6)

We need to show that car A is safer than car B and this is done by showing that the force is greater on car B than car A. Start by finding the force on car A, total mass 1580kg: Force is the change of moment...
JF
Answered by Jake F. • Physics tutor
13686 Views

A lamp has a rating of 18V 9W. How much energy is transferred to the bulb in 5 minutes? Calculate the current through it when connected to a 18V supply.

The first question comes from the realisation that the power rating, "9W" represents 9 joules being supplied every second and so can be written as 9 J/s and so in 5 minutes (or 300 seconds) the ene...
AN
Answered by Alexander N. • Physics tutor
5226 Views

Resistors of 5 ohms and 10 ohms are connected in series with a battery supplying 3 volts. What is the total resistance ? And calculate the current in the circuit.

For the first part of the question we note that the resistors are in series, this means we can simply add together the resistance, giving a value of: 15 ohms For the second part we use the equation V=IR, sub...
AN
Answered by Alexander N. • Physics tutor
20203 Views

On a see-saw Mary, weight 600N balances John, weight 200N when she sits 1.5m away from the pivot. How far from the pivot is John?

Using the knowledge that the moments are balanced, we can create an equation to calculate the distance John is from the pivot: 600N 1.50m = 200N (distance) (600/200)*1.5 = distance distance = 4.5m
AN
Answered by Alexander N. • Physics tutor
12878 Views

The loudspeaker produces a sound wave with a frequency of 850 hertz and a wavelength of 0.4 metres. Calculate the speed of this sound wave. Give the unit

The speed of a wave is given by "Frequency*Wavelength=Wave speed". Hence, the speed is 340. With the units of speed being m/s
AN
Answered by Alexander N. • Physics tutor
10575 Views