Một dây dẫn dài 100m ,tiết diện 2mm2 có điện trở 12 ôm. Tìm chiều dài của 1 dây đồng chất khác có tiết diện S2=0.4mm2 có điện trở gấp 5 lần điện trở dây 1

Asample of a gaseous substance changes into a liquid

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 790 n/m. it is initially at rest on an inclined plane that is at an angle of 28 degrees with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is k = 0.14. in the initial position, where the spring is compressed by a distance of a = 0.18 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

Asmall 21 kilogram canoe is floating downriver at a speed of 1 m/s. what is the canoe's kinetic energy?