Mechanics help needed plz

Sorry for not posting on subjects board - there hasn't been much activity on there recently....anyway here's the question.....

A car, of mass 1000kg, tows a caravan of mass 700kg along a straiht horizontal road. The force produced by the engine of the car is 3500N and the resistances to motion acting on the car and caravn are 650N and 320N respectively. Determine:

a) the acceleration of the car and caravan
b) the tension in the towbar

Could anyone plz check if the following solution is right....?

a) 3500 - 650 = 1000a
=> 2850 = 1000
=> a=2.85m/s2

b) T -320 = 700(2.85)
T=2315N

Reply 1

Notnek

Your solution is wrong
If you use tension in part (a):

1) 3500-650-T=1000a
2) T-320=700a

1) + 2):
2530=1700a
a=1.49 (3sf)

From there you can work out part (b)