Question

A 10kg toy truck has a 5kg toy car at rest. If the toy truck was moving at 3 m/s before the collision and carries that car with it, what is the
Final velocity of the car and truck.
A. 15 m/ s
B. 30 m/ s
C 2 m/ s
D. 18 m/ sc free

Answer 1

Answer:

Let m1 = mass of big toy car=10kg

m2= mass of small toy car= 5kg

U1= initial velocity of big toy car= 3m/s

U2= initial velocity of small toy car=0

Since the big toy car moved the small one after the collision, their final velocity will be the same.

m1u1 + m2u2= (m1+m2)v

10(3)+(5)(0)=(10+5)v

30=15v

Divide both sides by 15

V=2

The final velocity is 2m/s

Explanation:

Answer 2

Answer:

$v_f=2\:\mathrm{m/s}$

Explanation:

From the Law of Conservation of Momentum, momentum is conserved. Therefore, we can set up the following equation:

$m_1v_1+m_2v_1=m_fv_f$

Since the 5kg toy car was initially and rest, $m_2v_2=0$.

Therefore, plugging in our values, we have:

$10\cdot 3=(10+5)v_f,\\v_f=\frac{30}{15},\\v_f=\fbox{ 2\:\mathrm{m/s} }$.