Kradgor
Badges: 0
Rep:
?
#1
Report Thread starter 4 years ago
#1
A car of mass 650kg is travelling on a straight road inclined to the horizontal 5 degrees. At a certain point P on the road the car's speed is 15ms^-1. The point Q is 400 metres down the hill from P, and at Q the car's speed is 35ms^-1. For the motion from P to Q, find:

(a) The increase in kinetic energy of the car,
(b)The decrease in gravitational potential energy of the car
(c)Neglecting any resistances to the car's motion, and assuming that the car's engine produces a constant tractive force on the car as it moves down the hill from P to Q, calculate the magnitude of the tractive force and the power of the car's engine when the car is at Q.

So I need to do this without SUVATS (It's homework) and am stuck on the last part, any help is appreciated!
0
reply
the bear
Badges: 20
Rep:
?
#2
Report 4 years ago
#2
the increase in KE is the loss of GPE + work done by the engine

work done by engine = tractive force x distance covered going down the slope.

the power will be tractive force x velocity at Q
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

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

Personalise

Feeling behind at school/college? What is the best thing your teachers could to help you catch up?

Extra compulsory independent learning activities (eg, homework tasks) (13)
7.69%
Run extra compulsory lessons or workshops (28)
16.57%
Focus on making the normal lesson time with them as high quality as possible (27)
15.98%
Focus on making the normal learning resources as high quality/accessible as possible (24)
14.2%
Provide extra optional activities, lessons and/or workshops (45)
26.63%
Assess students, decide who needs extra support and focus on these students (32)
18.93%

Watched Threads

View All