Answer:
1977.696 J
Explanation:
Given;
Weight of the box = 28.0 kg
Force applied by the boy = 230 N
angle between the horizontal and the force = 35°
Therefore,
the horizontal component of the force = 230 × cosθ
= 230 × cos 35°
= 188.405 N
Coefficient of kinetic friction, μ = 0.24
Force by friction, f = μN
here,
N = Normal force = Mass × acceleration due to gravity
or
N = 28 × 9.81 = 274.68 N
therefore,
f = 0.24 × 274.68
or
f = 65.9232 N
Now,
work done by the boy, W₁ = 188.405 N × Displacement
= 188.405 N × 30
= 5652.15 J
and,
the
work done by the friction, W₂ = - 65.9232 N × Displacement
= - 65.9232 N × 30 m
= - 1977.696 J
[ since the friction force acts opposite to the direction of motion, therefore the workdone will be negative]
Answer:
Momentum is conserved.
Explanation:
-Momentum is conserved.
-By Newton's third law (For every action, there is an equal and opposite reaction.)-the change in momentum of gases in one direction must be balanced by an equal change in momentum of the spacecraft in the opposite direction.
Rotational speed of an object around an axis is the numbers of turns of the object divided by time. <span />
Answer:
Therefore the escape velocity from Mar's gravity is 
m/s.
Explanation:
Escape velocity: Escape velocity is a the minimum velocity that a object needs to escape from the gravitational field of massive body.
Escape velocity
G=Universal gravitational constant = 6.673×10⁻¹¹N m²/Kg²
M= mass of Mars = 6.42×10²³ kg
R = Radius of the Mars = 3.40×10³m
The escape velocity does not depend on the velocity of a object.
m/s
Therefore the escape velocity from Mar's gravity is m/s.
