A plate glass window (n = 1.5 has a thickness of 3.6 mm. how long does it take light to pass perpendicularly through the plate?
1 answer:
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Answer:
175.3 N
Explanation:
The motion of the ball is a uniform circular motion, therefore the net force on it must be equal to the centripetal force.
There are two forces acting on the ball at the lowest point of motion:
- The tension in the string, T , upward
- The weight of the ball, , downward
The net force (centripetal force) has the same direction as the tension (upward, towards the centre of the circular path), so we can write:
where the term on the right is the expression for the centripetal force, and where:
T is the tension in the string
is the weight of the ball
is the mass of the ball
v = 5.7 m/s is the speed of the ball at the lowest point
r = 4.4 m is the length of the rope, so the radius of the circle
Solving for T, we find the tension in the string: