# Physics help

Watch
Announcements
#1
I'm not too sure how to answer this question ...

A train on a straight level track is pulled at a constant speed of 23m/s by an engine with an output power of 700kW.

the train then moves on to an inclined section of the railway line where the track rises by 1m for kilometre of track. Explain why the output power of the engine needs to be increased to maintain the same speed of 23m/s.

I have written an answer I effectively said that it is because more work is done therefore more energy is transferred( because the energy is being transferred into gravitational potential energy as the track rises) rather than useful kinetic energy. so more power is needed. - I'm not sure if this is right
0
4 years ago
#2
(Original post by znk123)
I'm not too sure how to answer this question ...

A train on a straight level track is pulled at a constant speed of 23m/s by an engine with an output power of 700kW.

the train then moves on to an inclined section of the railway line where the track rises by 1m for kilometre of track. Explain why the output power of the engine needs to be increased to maintain the same speed of 23m/s.

I have written an answer I effectively said that it is because more work is done therefore more energy is transferred( because the energy is being transferred into gravitational potential energy as the track rises) rather than useful kinetic energy. so more power is needed. - I'm not sure if this is right
The energy isn't being transferred into gravitational potential energy, but rather kinetic energy in order for the train to move on the inclined plane against gravity (in a more general sense: if an object is lifted, work is done against gravitational force, so the object gains energy in order to move against gravity).

Do you know the equation for power? Power = Force x distance = the rate of doing work = energy transformed / time.
0
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

#### Would you give consent for uni's to contact your parent/trusted person in a mental health crisis?

Yes - my parent/carer (119)
33.9%
Yes - a trusted person (95)
27.07%
No (93)
26.5%
I'm not sure (44)
12.54%