# tension

• May 2nd 2008, 01:12 PM
helpishere
tension
A car towing a trailer along a straight horizontal road.
The mass of the car is 1200kg and the mass of the trailer is 600kg
The car's engibe produces a forward force of 5400N
The car and trailer have an acceleration of 2.5m/s^2

i)find the total resistance acting on the car and the trailer

This resistance is dicided between the car and the trailer in the same ratio as their masses.
ii)Find the tension in the towbar connecting the car and the trailer.

Thanks
• May 2nd 2008, 01:44 PM
hi there,

part i)

well basically this is Newton's second law of motion, F=ma;
where,
F = resultant force acting on the system(car and trailer)
m = mass (car and trailer)
a = acceleration (car and trailer)

therefore applying Newtons second law of motion:
Driving force - Frictional force = ma
5400 - Frictional force = ma
Frictional force = 5400 - ma = R

part ii)

the ratio of mass of the car to that of the trailer= 1200:600 = 2:1
therefore,
the frictional force acting on the car = $\frac{2}{3}R$
the frictional force acting on the trailer = $\frac{1}{3}R$

considering the trailer:

now it is given that the trailer is accelerating at $2.5ms^{-2}$, using Newton's second law of motion again:

tension in the towbar - frictional force on the trailer = $m_t a$
where,
$m_t$=mass of the trailer = 600kg

tension in towbar = $m_t a$ +frictional force on the trailer.

I think you can continue from here. good luck in finding the answer ^-^