In the northern hemisphere, are the day lengths greater of less than 12 hours between the winter solstice and the spring equinox?

A2k pendulum has a speed of 1 m/s at a height of 1/2 meter

An ideal otto cycle has a compression ratio of 10.5, takes in air at 90 kpa and 40°c, and is repeated 2500 times per minute. using constant specific heats at room temperature, determine the thermal efficiency of this cycle and the rate of heat input if the cycle is to produce 90 kw of power.

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration