Một bánh xe (có dạng là hình trụ rỗng) bán kính 0.5m, khối lượng m=50kg. Bánh xe chịu tác dụng bởi một lực tiếp tuyến Ft=100N. a. Gia tốc của bánh xe. b. Bao lâu kể từ khi lúc bắt đầu tác dụng lực thì bánh xe có được tần số

N =100 vòng /phút. Giả thiết lúc đầu xe đứng yên.

Suppose that two tanks, 1 and 2, each with a large opening at the top, contain different liquids. a small hole is made in the side of each tank at the same depth 1.57 m below the liquid surface, but the hole in tank 2 has 2.49 times the cross-sectional area of the hole in tank 1. (a) what is the ratio ρ1/ρ2 of the densities of the liquids if the mass flow rate is the same for the two holes? (b) what is the ratio rv1/rv2 of the volume flow rates from the two tanks? (c) at one instant, the liquid in tank 1 is 14.9 cm above the hole. if the tanks are to have equal volume flow rates, what height above the hole must the liquid in tank 2 be just then?

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

An ionic compound can conduct electricity when a it is dissolved in water b its crystals are ground into powder c it is in solid form d it is heated to just below its melting point