Circular motion, gravitational field, and oscillation
1.Define gravitational field strength:
Force per unit mass
2. Explain why there is a point between two point masses at which the gravitational field strength is zero. Because gravitational fields of two masses are in opposite directions, so there is a point where it is zero
What is meant by angular velocity
The rate of change of the angular displacement of an object as it moves along curved path.
Generally when asked to test a equation, we need to balance the centripetal force with gravitational force.
Define the radian
angle at centre of circle, arc equal in length to radius
State and explain whether the motion of the ball is simple harmonic. (such as a ball bounce) acceleration is constant (g), so cannot be s.h.m.
Oscillations: a repetitive back-and forth motion
Free oscillations: no energy loss or gain
Simple harmonic motion: acceleration directed towards a fixed point, and acceleration proportional to distance from the fixed point.
Thermodynamics and ideal gas
1.State the basic assumptions of the kinetic theory of gases. -atoms behave as elastic spheres
-volume of atoms negligible compared to volume of containing vessel -time of collision negligible to time between collisions
-no forces of attraction or repulsion between atoms.
-atoms are in random motion
I.State the basic assumption of the kinetic theory of gases that leads to the conclusion that the potential energy between the atoms of an ideal gas is zero. no forces between atoms
II.Suggest why the assumption made in XX may not be valid.
One of above 5 assumption is not validate.
2.State what is meant by the internal energy of a substance. sum of kinetic and potential energy of atoms / molecules, due to random motion.
3.Explain why an increase in internal energy of an ideal gas is directly related to a rise in temperature of the gas.
kinetic energy increases with...
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