Question

In a closed system, a cart with a mass of 1.5 kg is rolling to the right at 1.4 m/s, while another cart of mass 1.0 kg is rolling to the left at the same speed. What is the total momentum of the system of two carts?
a. 0.0 kgm/s

b. 0.50 kgm/s

c. 0.70 kgm/s

d. 3.5 kgm/s

Answer 1

Answer: The correct option is (c.).

Explanation:

Mass of the cart A= 1.5 kg

Velocity of Cart A = 1.4 m/s towards right

Mass of the cart B = 1.0 kg

Velocity of Cart B = 1.4 m/s towards left

Momentum (P)= Mass × Velocity

$P_A=1.5 kg\times 1.4 m/s=2.1 kg m/s$

$P_B=1.0 kg\times (-1.4m/s)=-1.4 kg m/s$

(Negative sign means velocity of the cart is in opposite direction of that of the cart A)

Total Momentum =$P_A+P_B=2.10 kg m/s-1.40 kg m/s=0.70 kg m/s$

Hence, the correct option is (c.).

Answer 2

The momentum is equal to m*v
m is mass
v is speed
so 1.5 kg*1.4m/s + 1 kg*1.4m/s
2.5kg*1.4m/s
3.5 kgm/s
hope it helps