Answer:
d) v1 = v2 = v3
Explanation:
This can be answered using conservation of energy. We calculate the mechanical energy E=K+U (sum of kinetic and gravitational potential energies) at the original and final points, and impose they are equal.
At the original point we have, for the three balls:
At the final point we have, for the three balls:
Since we have 
, and 
is the same for all balls, then 
is the same for all balls, which means that 
, the final velocity, is the same for all balls.
Actually the question is not clear. The Benefit of lifting using lever is that you can apply force in a convenient direction and you can use very less force to lift object by balancing the torque due to object.For example you want to lift a mass of 4N with a force 2N you can use a class 2 lever and maintain the ratio between the distances of the body and the point of application of force from the fulcrum to be 1:2.In any case balance the torque to get the required force.
What is the coefficient of kinetic friction between the block and the surface? Express your answer using two significant figures.
Answer:
0.39
Explanation:
Given information
m1=1.7 Kg
m2=0.011 Kg
v2=670 m/s
d=2.4 m
m2v2=(m1+m2)v hence 
and also 
The deceleration due to friction is given by
therefore 
Therefore, 
Answer:
3. 5.0N/kg
Explanation:
Gravitational field strength = gravitational force/mass of astronaut = 350N/70kg = 5.0N/kg
