Which describes a positive or negative net force acting on an object? Check all that apply. DIt can cause an object to accelerate.
Olt can cause an object to stop moving.
Olt can cause an object to start moving.
Dit can cause an object to change directions.
Ult can cause an object at rest to remain at rest.

Estimate the kinetic energy of mars with respect to the sun as the sum of two terms, that due to its daily rotation about its axis, and that due to its yearly revolution about the sun. (assume mars is a uniform sphere with mass = 6.4×10 to the power of 23 kg, radius = 3.4×10 to the power of 6 m, rotation period = 24.7 hours, orbital period = 686 days and is 2.3×10 to the power of 8 km from the sun.)