Answer:
<h2>1) there is no work done on the system</h2><h2>2) A) Using a lever to lift 100 newtons up to 4 meters on to a shelf</h2><h2 /><h2>3) P = 140 W</h2><h2>4) D) In a closed system, a system that isolated from its surrounds, the total energy of the system is conserved</h2>
Explanation:
1) As we know that work done is the product of force and the displacement of the point of action where force is applied
So here we have

as there is no displacement in the direction where the force is applied
2)As we know that work is product of force and displacement
So we will have




So maximum work is done on
A) Using a lever to lift 100 newtons up to 4 meters on to a shelf
3)
As we know that power is rate of work done
so we have



4)
As per energy conservation we know that
D) In a closed system, a system that isolated from its surrounds, the total energy of the system is conserved
Answer:
933. 3kg
Explanation:
We are given that
Mass,m=2000 kg
Initial speed,u=4.4 m/s
We have to find the maximum mass of grain if the speed of loaded freight car must not go below 3.0 m/s.
Final speed,v=3 m/s
By conservation of momentum
Initial momentum=Final momentum

Substitute the values



Mass of freight loaded car=2933.3 kg
Mass of grains=2933.3-2000=933.3 kg
Hence, the maximum mass of grains that it can accept=933.3 kg
Answer:
1. 310 N
2. 310 N
Explanation:
1. Determination of the net force.
Force applied (Fₐ) = 430 N
Force experience (Fₑ) = 120 N
Net force (Fₙ) =?
Fₙ = Fₐ – Fₑ
Fₙ = 430 – 120
Fₙ = 310 N
Hence, the net force acting on the crate is 310 N
2. Determination of the net force.
Force applied (Fₐ) = 375 N
Force of friction (Fբ) = 65 N
Net force (Fₙ) =?
Fₙ = Fₐ – Fբ
Fₙ = 375 – 65
Fₙ = 310 N
Hence, the net force acting on the crate is 310 N.
Answer:
the bike would not be moving
Explanation:
They keep the astronauts safety as a priority. They also try to stay in budget, but mainly the astronauts safety is most important.