A block lies on a frictionless floor. a force of 5 n pulls toward the east while a force of 4 n pulls toward the north. what is
the magnitude of the net force on the block?
1 answer:
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If we pull an object vertically upwards then we need to apply a force which is equal in the magnitude of the weight of the object
now when we pull the same object upwards along an inclined plane with angle then we require a force which will balance the component of weight along the inclined
so it is given as
so as if we compare the two forces we can say that since the value of sine is always less than 1 for an angle less than 90 degree
so in the 2nd case when we pull the object along the inclined plane it will require less effort
so correct answer is
<em>A. reduce effort</em>
1) Initial upward acceleration:
2) Mass of burned fuel:
Explanation:
1)
There are two forces acting on the rocket at the beginning:
- The force of gravity, of magnitude , in the downward direction, where
is the rocket's mass
is the acceleration of gravity
- The thrust of the motor, T, in the upward direction, of magnitude
According to Newton's second law of motion, the net force on the rocket must be equal to the product between its mass and its acceleration, so we can write:
(1)
where a is the acceleration of the rocket.
Solving for a, we find the initial acceleration:
2)
When the rocket reaches an altitude of 5000 m, its acceleration has increased to
The reason for this increase is that the mass of the rocket has decreased, because the rocket has burned some fuel.
We can therefore rewrite eq.(1) as
where
is the new mass of the rocket
Re-arranging the equation and solving for m', we find
And since the initial mass of the rocket was
This means that the mass of fuel burned is