A railway truck P, of mass m kg, is moving along a straight horizontal track with speed 15 ms⁻¹ - Edexcel - A-Level Maths Mechanics - Question 1 - 2012 - Paper 1

To find the mass m of truck P, we can use the principle of conservation of linear momentum. The total momentum before the collision must equal the total momentum after the collision:

$ext{Initial momentum} = ext{Final momentum}$

The initial momentum is:

$15m ext{ kg m/s}$

And the final momentum, taking the directions into account, is:

$-3m + 27000 ext{ kg m/s}$

Setting these equal gives:

$15m = -3m + 27000$

Solving for m:

$15m + 3m = 27000$ $18m = 27000$ $m = \frac{27000}{18} = 1500 ext{ kg}$

So, the mass of truck P is 1500 kg.