Maths question - HELP!!

A toy helicopter of mass 0.2 kg has its rotors set so that the force provided by the engine is given by F = a i + b j, where a and b can be varied using a remote control, but the magnitude of F is always 3 N. The unit vector i is horizontal, and j is vertical. Use g = 9.8 m/s², giving your final answers to an appropriate degree of accuracy.

(a) What is the acceleration if the helicopter is set to fly horizontally?

(b) The helicopter accelerates at 45° above the horizontal. How long would it take for the helicopter to travel 5 metres?

I don't understand how to do the diagram for this, and how to label it properly. Can someone explain this in an easy way?

Reply 1

mqb2766

Original post

by MaaSaraswati

A toy helicopter of mass 0.2 kg has its rotors set so that the force provided by the engine is given by F = a i + b j, where a and b can be varied using a remote control, but the magnitude of F is always 3 N. The unit vector i is horizontal, and j is vertical. Use g = 9.8 m/s², giving your final answers to an appropriate degree of accuracy.
(a) What is the acceleration if the helicopter is set to fly horizontally?
(b) The helicopter accelerates at 45° above the horizontal. How long would it take for the helicopter to travel 5 metres?
I don't understand how to do the diagram for this, and how to label it properly. Can someone explain this in an easy way?

A force diagram? What are you unsure about? i is horziontal, j is vertical so it shouldnt be that hard. Have a go and upload what you think

(edited 11 months ago)

Reply 2

MaaSaraswati

Original post

by mqb2766

A force diagram? What are you unsure about? i is horziontal, j is vertical so it shouldnt be that hard. Have a go and upload what you think

Yeah but what about 3N? Which direction is it in?

Reply 3

mqb2766

Original post

by MaaSaraswati

Yeah but what about 3N? Which direction is it in?

The force is
ai + bj
and 3N represents the magnitude, so the hypotenuse of the right triangle with legs a and b. So the direction is determined by the values of a and b.