Because the molecules that move freely begin to compact closer together, with less heat, means less molecular activity.
Answer:
Part a)
Part b)
Ball thrown downwards =
Ball thrown upwards =
Part c)
Explanation:
Part a)
Since both the balls are projected with same speed in opposite directions
So here the time difference is the time for which the ball projected upward will move up and come back at the same point of projection
Afterwards the motion will be same as the first ball which is projected downwards
so here the time difference is given as
Part b)
Since the displacement in y direction for two balls is same as well as the the initial speed is also same so final speed is also same for both the balls
so it is given as
Part c)
Relative speed of two balls is given as
now the distance between two balls in 0.8 s is given as
It's not so much a "contradiction" as an approximation. Newton's law of gravitation is an inverse square law whose range is large. It keeps people on the ground, and it keeps satellites in orbit and that's some thousands of km. The force on someone on the ground - their weight - is probably a lot larger than the centripetal force keeping a satellite in orbit (though I've not actually done a calculation to totally verify this). The distance a falling body - a coin, say - travels is very small, and over such a small distance gravity is assumed/approximated to be constant.
The type of medium affects a sound wave as sound travels with the help of the vibration in particles. As different mediums have different amount and size of particles, for example, the speed of sound is faster through solid than liquid as solids have closely packed particles whereas liquids are loosely packed. Therefore the vibration is quicker in solids than liquids.
Hope it helps you! :)
A concave mirror is used in the design of solar furnaces because they converge the parallel sunrays at a point. This helps to increase the temperature of the furnace.
