Answer:
The toy car. An object that isn't moving has no momentum
Explanation:
James E. Hansen studied climate change
Answer:
the velocity of the boats after the collision is 4.36 m/s.
Explanation:
Given;
mass of fish, m₁ = 800 kg
mass of boat, m₂ = 1400 kg
initial velocity of the fish, u₁ = 12 m/s
initial velocity of the boat, u₂ = 0
let the final velocity of the fish-boat after collision = v
Apply the principle of conservation of linear momentum for inelastic collision;
m₁u₁ + m₂u₂ = v(m₁ + m₂)
800 x 12 + 1400 x 0 = v(800 + 1400)
9600 = 2200v
v = 9600/2200
v = 4.36 m/s
Therefore, the velocity of the boats after the collision is 4.36 m/s.
Answer:
Explanation:
Work done by the spring is negative .
Work done by force F creating displacement d is given by the following expression .
Work = F x d
Both force and displacement are vector quantity .
When direction of force and direction of displacement is same , work is positive . When direction of force and direction of displacement is opposite , work is negative .
When spring is compressed , it exerts a restoring or opposing force in a direction opposite to the direction of displacement of box . Hence here force is opposite to displacement . Restoring force acts opposite to displacement . Hence work done by spring on box is negative .
Answer:
3099 J
Explanation:
The increase in thermal energy corresponds to the mechanical energy lost in the process.
The mechanical energy is given by the sum of gravitational potential energy and kinetic energy of the fireman:
At the top of the pole, the fireman has no kinetic energy, so all his mechanical energy is just potential energy:
When the fireman reaches the bottom, he has no gravitational potential energy, so his mechanical energy is just given by his kinetic energy:
So, the loss in mechanical energy was
and this corresponds to the increase in thermal energy.
