Question

A boy whose mass is 40 kilograms runs at 5 meters per second and jumps onto a 10-kilogram stationary sled. The boy slides on the sled over a horizontal, frictionless surface at a speed of:

a. 2 m/sec.
b. 4 m/sec.
c. 5 m/sec.
d. 10 m/sec.

Answer 1

After the boy jumps onto the sled, they slide together at a speed of 4 m/s, calculated using the conservation of momentum since the surface is frictionless.

Step-by-step explanation:

The subject of this question is Physics, specifically focusing on the principle of conservation of momentum. In the scenario described, a 40-kilogram boy runs at 5 meters per second and jumps onto a 10-kilogram stationary sled. Since there are no external forces acting on the system (frictionless surface), the total momentum of the system before and after the boy jumps onto the sled must be conserved.

To find the speed at which the boy and the sled move together, we use the formula for conservation of linear momentum:

Momentum before = Momentum after

(mass of boy * velocity of boy) + (mass of sled * velocity of sled) = (combined mass) * (final velocity)

(40 kg * 5 m/s) + (10 kg * 0 m/s) = (40 kg + 10 kg) * (final velocity)

200 kg*m/s = 50 kg * (final velocity)

Therefore, the final velocity is:

final velocity = 200 kg*m/s / 50 kg

final velocity = 4 m/s