If the crate shown here is moving at a constant speed in a straight line and the force applied is 310 N, what is the magnitude o
f the force of friction?
A.310 N
B.0 N
C.620 N
A.310 N
B.0 N
C.620 N
1 answer:
Answer:
the answer is A.
Explanation:
Using the laws of newton:
∑F = ma
where ∑F is the sumatory of forces acting in the system, m the mass and a the acelertion of the system.
Then, if the block is moving with constant velocity, its aceleration is equal to 0, so:
∑F = m(0)
∑F = 0
It means that:
F - = 0
where F is the force applied and is the friction force. Replacing the value of F, we get:
310N - = 0
Finally, solving for :
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Answer:
None of the statement is false - all of them are true
Explanation:
Let's analyze each statement:
- The net force on the block is zero newtons. --> TRUE. In fact, the block is moving across the surface at constant speed: constant speed means zero acceleration, and according to Newton's second law,
F = ma
this also means a net force of zero newtons.
- The frictional force on the block has magnitude 3.0 N. --> TRUE. The horizontal acceleration of the block is zero, so the resultant of the horizontal forces must be zero:
where F = 3.0 N is the horizontal push and is the frictional force. From the equation, we find
- The coefficient of kinetic friction between the block and the surface is 0.30. --> TRUE. The frictional force is 3.0 N, and its expression is
where is the coefficient of kinetic friction and (mg)=10 N is the weight of the block. Solving for
, we find
- The direction of the total force that the surface exerts on the block is vertically upward. --> TRUE. Since gravity is acting downward, and the block is not accelerating on the vertical direction neither, there must be an equal and opposite force acting upward on the block: and this force is the force exerted by the surface on the block.
- The block is not accelerated. --> TRUE: the block is moving at constant speed, so its acceleration is zero.
Answer
given,
mass of satellite = 2400 Kg
speed of the satellite = 6.67 x 10³ m/s
acceleration of satellite = ?
gravitational force of the satellite will be equal to the centripetal force
Assuming the radius of circular orbit = 8.92 x 10⁶ m
now,
F = 11970.11 N
acceleration,
a = 4.98 m/s²