Question

24.A 2,500 kg car traveling at 20 m/s crashes into a 6,000 kg truck
that is originally at rest. What is the speed of the truck after the
collision, if the car comes to rest at the point of impact? (Neglect
the effects of friction.)
A. O m/s
8. 8.33 m/s
C. 16.7 m/s
D. 83 m/s
E.14 m/s​

Answer 1

Given info : A 2,500 kg car traveling at 20 m/s crashes into a 6,000 kg truck

that is originally at rest.

To find : the speed of the truck after the collision, if the car comes to rest at the point of impact.

Solution : using law of conservation of linear momentum,

Initial linear momentum = final linear momentum

Here initial linear momentum = m₁u₁ + m₂u₂

initial velocity of car, u₁ = 20 m/s

initial velocity of truck, u₂ = 0

So, initial linear momentum = 2500 × 20 kgm/s + 0 = 50,000 kgm/s

Final linear momentum = m₁v₁ + m₂v₂

final velocity of car, v₁ = 0 m/s

final velocity of truck, v₂ = ?

so, final linear momentum = 2500 × 0 + 6000 × v₂ = 6000v₂

Now, initial linear momentum = final linear momentum

⇒50,000 = 6,000v₂

⇒v₂ = 50/6 = 8.33 m/s

Therefore the speed of the truck after collision is 8.33 m/s

Answer 2

Please find the answer attached below.