Explanation:
a. KE at bottom = PE at top
½ mv² = mgh
v = √(2gh)
v = √(2 × 9.8 m/s² × 20.0 m)
v = 19.8 m/s
b. Work by friction = PE at top
mgμ d = mgh
d = h / μ
d = 20.0 m / 0.210
d = 95.2 m
Friction is the resistance offered against the motion of one surface over the other. This is because, at the microscopic level, each surface has hills and valleys i.e. the surfaces are not completely smooth and hence the roughness of one surface locks over the other and restricts its motion. There are two kinds of friction: static friction and kinetic friction. When the object is at rest, static friction acts. While the object is in motion, kinetic friction acts. Static friction is greater than the kinetic friction because a larger force is required to change the state of rest to motion. You must have experienced that if you do not accelerate the bike while its in motion, it would slow down and eventually stop. In order to get the bike moving, initially static friction must be overcome and thereafter, kinetic friction to make it stay in motion.
Answer: time; mass
Explanation:
The equation E=mc^2 shows that energy, e, and mass, m, are linked.
For objects moving in a straight line, the special theory of relativity applies to show that space and time are linked.
Answer:
he spring provides the controlling torque. The air friction induces the damping torque, which opposes the movement of the coil. The repulsion type instrument is a non-polarized instrument, i.e., free from the direction of current passes through it. Thus, it is used for both AC and DC
Answer:
1: an object will stay still until acted on by another force
2: acceleration of an object depends on the mass of the object and the force applied
3: for every action there is an equal and opposite reaction
