What is instantaneous velocity

Why did ptolemy have to introduce multiple circles of motion for the planets instead of a single, simple circle to represent the planetâs motion around the sun?

Atrain departs from its station at a constant acceleration of 5 m/s. what is the speed of the train at the end of 20s?

According to newton's second law, when the same force is applied to two objects of different masses, a the object with greater mass will experience a great acceleration, and the object with less mass will experience an even greater acceleration, b. the object with greater mass will experience a smaller acceleration, and the object with less mass will experience a greater acceleration, c. the object with greater mass will experience a greater acceleration, and the object with less mass will experience a smaller acceleration, d. the object with greater mass will experience a small acceleration, and the object with less mass will experience an even smaller acceleration.