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# AS physics question help. watch

1. Please could someone explain how you work these 2 questions out!

1) A ball on a snooker table is hit by another ball and travels a distance of 50cm due west. it is then hit again and travels a distance of 30cm due north. Using a scale drawing or by calculation work out the displacement from its starting position.

2) A ship is travelling at 5ms^-1 with a bearing of 20degrees east of north. There is a current of 1ms^-1 flowing from the west. What is the resultant velocity of the ship

2. (Original post by mujahid_e3)
Please could someone explain how you work these 2 questions out!

1) A ball on a snooker table is hit by another ball and travels a distance of 50cm due west. it is then hit again and travels a distance of 30cm due north. Using a scale drawing or by calculation work out the displacement from its starting position.
West is at right angles to North, so construct a right angle triangle, and use Pythagoras to find the displacement.

2) A ship is travelling at 5ms^-1 with a bearing of 20degrees east of north. There is a current of 1ms^-1 flowing from the west. What is the resultant velocity of the ship
Again draw a diagram of the forces and then split each force into horizontal and vertical components, then find the resultant using the components.
3. With the fist one mark the starting position and then trace the path it takes. You should end up with a triangle. The displacement is the shortest distance from the start point to the end point so use pythagoras' theorem to work out the missing side of your triangle.

The second one is really similar, only this time draw some arrow heads on your lines to indicate the direction. Then look at your two lines and judging by the position of the arrows and their direction draw the resultant arrow in with its direction. The magnitude of the speed is done the similar to the first question. You need to find the size of the last unknown arrow. Sonce this is no longer a right angle you will need to use the sin rule/ cos rule to work out your missing length. Since you are working out velocity and not speed you will also need your direction and hence the missing angle. You can work out missing angles using sin/cos rule and then say it is however many degrees north/south etc.

Hopefully you know rhe sin/cos rule and pythag otherwise google is the answer (or somebody on TSR)
4. For question 1.) If you draw a line 5cm long and then another line 3cm long at an right angle to the first line (starting from one end of the first line)

Then if you draw a diagonal line connecting the ends you should get a right angled triangle. The length of this new diagonal line will be its displacement because the displacement is the total distance from the starting point (As the crow flies).
5. Could tell me answer of my question.
My question is that"could we measure displacement current through AMMETER?"
if yes kindly describe me the reason of behind it.

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