An electric hoist does 500 joules of work lifting a crate 2 meters. How
1 answer:
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Answer:
Explanation:
Given:
- mass of the object on a horizontal surface,
- coefficient of static friction,
- coefficient of kinetic friction,
- horizontal force on the object,
<u>Now the value of limiting frictional force offered by the contact surface tending to have a relative motion under the effect of force:</u>
where:
normal force of reaction acting on the body= weight of the body
As we know that the frictional force acting on the body is always in the opposite direction:
So, the frictional force will not be at its maximum and will be equal in magnitude to the applied external force and hence the body will not move.
so, the frictional force will be:
Answer:
The correct answer to the question is
B. It always decreases
Explanation:
To solve the question, we note that the foce of gravity is given by
where
G= Gravitational constant
m₁ = mass of first object
m₂ = mass of second object
r = the distance between both objects
If the mass of one object remains unchanged while the distance to the second object and the second object’s mass are both doubled, we have
=
Therefore the gravitational force is halved. That is it will always decrease