Answer:
Zero
Explanation:
Work done is given by multiplying force and distance moved. The distance is moved both positive and negative and it's equal distance. Since force used is the same hence work
W=F*d+ (F*-d)=0
Therefore, total work done is zero
Answer; g
Explanation: the human is a lot smaller than the train
Answer:
The momentum of the ball is 500 kg·m/s
Explanation:
The momentum is given by Mass × Velocity
The given parameters are;
The mass of the box = 10 kg
The velocity by which the box is sliding = 50 m/s
Therefore, the momentum of the ball is given as follows;
The momentum of the ball = 10 kg × 50 m/s = 500 kg·m/s
The momentum of the ball = 500 kg·m/s
Suppose earth is a soid sphere which will attract the body towards its centre.So, acc. to law of gravitation force on the body will be,
F=G*m1m2/R^2
but we now that F=ma
and here accleration(a)=accleration due to gravity(g),so
force applied by earth on will also be mg
replace above F in formula by mg and solve,
F=G*mE*m/R^2 ( here mE is mass of earth and m is mass of body)
mg=G*mEm/R^2
so,
g =G*mE/R^2
