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A cyclist rides 10km. In the first 5km, they climb a hill, averaging 10km/h. In the second 5km, they descend the hill, averaging 30km/h. What is their average speed over the full 10km?

A common response from the student for the above question is: “I got 20km/h but it says it’s wrong! help i’m really confused”. The following two paragraphs will outline how I might attempt explain this idea ...
SB
Answered by Shihabul B. • Physics tutor
3785 Views

A hot air balloon is travelling at a speed of 5.0m/s at an angle of 60.0 degrees up from the horizontal. Find the vertical and horizontal components.

The diagram would have the following: An arrow pointing upwards labeled v(y) An arrow pointing to the right labeled v(x) An arrow pointing in between those lines with a degree between this one and the right ...
MB
Answered by Marta B. • Physics tutor
2725 Views

Define the resistivity of a metal wire

ρ = (AR) / l where: ρ is the resistivity of the metal wire A is the cross sectional area of the specimen wire R is the electrical resistance of a uniform metal wire l is the length of metal wire through whic...
JE
Answered by Javier E. • Physics tutor
3900 Views

A 15kg cannonball and a 1kg football are dropped to the ground from a height of 10 metres. Calculate the speed of the cannonball and of the football just before they hit the ground (you may ignore air resistance).

Aim of question: demonstrate that the speed of a dropped object is independent of its mass, and depends only on the height it is dropped from. Solution: equate formulae for kinetic energy and for gravitation...
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Answered by Will R. • Physics tutor
2765 Views

Calculate the momentum of a 5 tonne truck at 50km/h

We know momentum= mass (kg) X Velocity (m/s) So we need to do these conversions: 1tonne=1000kg so 5 tonnes is 5x1000kg = 5000kg There are 1000km in a meter so 50x1000= 50000m/h to get this into m/s we know t...
CZ
Answered by Callum Z. • Physics tutor
3156 Views