Question

1. A 1500 kg truck travelling north at 60 km/hr collides with a 1200 kg car
moving east at 15 km/hr. If the two cars remain locked together after
impact, with what velocity do they move immediately after the
collision?
​

Answer 1

Given:

A 1500 kg truck travelling north at 60 km/hr collides with a 1200 kg car moving east at 15 km/hr. The two cars remain locked together after impact.

To find:

Velocity after collisions?

Calculation:

We will apply CONSERVATION OF LINEAR MOMENTUM equation along both x and y axes.

Along X axis (i.e. East-West Direction):

$\sf (1500 \times 0 )+ (1200 \times 15) = (1500 + 1200) v_{x}$

$\sf \implies 18000 = 2700v_{x}$

$\sf \implies v_{x} = 6.66 \: kmph$

Along Y axis (i.e. North-South direction):

$\sf (1500 \times 60 )+ (1200 \times 0) = (1500 + 1200) v_{y}$

$\sf \implies 90000 = 2700v_{y}$

$\sf \implies v_{y} = 33.33 \: kmph$

Now, net velocity will be :

$\sf \: v = \sqrt{ {(33.3)}^{2} + {(6.66)}^{2} }$

$\sf \implies\: v = 33.98 \: kmph$

So, Velocity is 33.98 km/hr after collision.