Uniform Circular Motion Flashcards
What is uniform circular motion?
When objects travel at a constant speed, in circular motion, or portion of circular motion.
What it the direction of the velocity of any object in uniform circular motion?
Tangential.
If an object swings in uniform circular motion with a radius of 50.0 cm and a frequency of 2.00 Hz, what would its speed be?
V= 2Pi(radius)(frequency) V= 6.28 m/s
What type of force causes circular motion?
Centripetal force
How can an object traveling at a constant speed be accelerating? Explain.
Acceleration is caused by a change in velocity.
Velocity is a speed WITH direction. A change in direction is ALSO A VELOCITY CHANGE. Thus if an object is in UCM and is changing direction at every instant, it MUST be accelerating, even though its speed stays the same.
What is a period?
The length of time to complete one cycle (rotation).
Is ‘rpm’ a measure of period or frequency? Explain.
‘rpm’ is revolutions per minute, that is the number of cycles per minute. This can be converted to number of cycles per second, which is a FREQUENCY.
What direction is the acceleration of an object in circular motion?
Centripetal, radially toward the centre.
What is the centrifugal force?
The imaginary force, that APPEARS to be pushing the object radially outward.
What is the cenripetal force?
The real force, that actually CAUSES circular motion, pushing the object radialy inward.
As an object moves in vertical uniform circular motion what are two forces that must be acting on the object?
Force of gravity, and Force applied. The two add together to create the NET centripetal force. (Note: the Force applied has to continually compensate for the weight to ensure a constant net force)
Describe the size of the Force applied (Fapp) at the top, middle, and bottom of vertical uniform circular motion.
The force applied is the smallest at the top, larger in the middle, and largest at the bottom.
This is because at the top the weight is pulling centripetally, while at the bottom the weight is pulling away from the centre.
When children are playing on a merry-go-round, some children stand close to the centre, others stand midway toward the edge, and some hang on at the edge of the merry-go-round. If all the students have the same mass, how would the FORCE that they need to hang on vary?
The force applied required INCREASE as the students move away from the centre. The child on the outter edge of the merry-go-round has to hold on the hardest, the child near the centre has to hold on the least.
When children are playing on a merry-go-round, some children stand close to the centre, others stand midway toward the edge, and some hang on at the edge of the merry-go-round. If all the students have the same mass, how would their SPEEDS vary?
The child on the outter edge will be moving the fastest, the child near the centre will be moving the slowest.
An object, hanging from a string, is swung in uniform horizontal circular motion. How are the speed at which it is swung compare with the angle that the string makes with the vertical axis above the centre of the rotation, related?
The faster the motion, the larger the angle the object swings round with.
