Which is NOT an example of unbalanced forces acting on an object
1 answer:
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Answer:
2. The metal surface exerts less frictional force because there are fewer bumps and irregularities on it than there are on the concrete.
Explanation:
Frictional force is a force that is exerted between two surfaces in contact with each other. Frictional force always opposes the direction of relative motion of the two surfaces: for instance, for a ball moving along a surface, the force of friction exerted by the surface on the ball points opposite to the direction of motion of the ball.
The magnitude of the frictional force for a ball moving on a flat surface is given by
where
is the coefficient of friction
m is the mass of the ball
g is the acceleration of gravity
The value of depends on the type of surface involved. In particular, a smooth surface has a smaller value of
, while a rough surface will have a bigger value. In this case, we are comparing a smooth metal surface with concrete: since the metal surface has fewer bumps and irregularities than concrete, it has a smaller value of coefficient of friction, so it exerts less frictional force than concrete.
Answer:
Explanation:
Newton's law of universal gravitation states that the force experimented by a satellite of mass m orbiting Mars, which has mass at a distance r will be:
where is the gravitational constant.
This force is the centripetal force the satellite experiments, so we can write:
Putting all together:
which means:
Which for our values is:
Since this distance is measured from the center of Mars, to have the height above the Martian surface we need to substract the radius of Mars R=3389.5 km , which leaves us with: