Imagine you were able to throw a ball in a frictionless environment
such as outer space. Once you let go of the ball, it will travel forever
in a straight line, and at a constant speed. (At least until it bumps into
something.)
A car accelerates down the road. The reaction to the tires pushing
on the road is the road pushing on the tires.
Answer:
C
Explanation:
Chemical reaction,physical
Answer:
659.01W
Explanation:
The cab has a mass of 1250 kg, the weight of the cab represented by Wc will be
Wc = mass of the cab × acceleration due to gravity in m/s²
Wc = 1250 × 9.81 = 12262.5 N
but the counter weight of the elevator represented by We = mass × acceleration due to gravity = 995 × 9.81 = 9760.95 N
Net weight = weight of the cab - counter weight of the elevator = Wc - We = 12262.5 - 9760.95 = 2501.55 N
the motor of the elevator will have to provide this in form of work
work done by the elevator to lift the cab to height of 49 m = net weight × distance (height) = 2501.55 × 49m
power provided by the motor of the elevator = workdone by the motor / time in seconds
Power = (2501.55 × 49) ÷ ( 3.1 × 60 seconds) = 659.01 W
<span>Different materials expand and contract at different rates based on temperature. Just like if you leave a plastic bottle full of water in a freezer it will burst, but if you leave it partially full no problem.....Ok?Expansion joints do the same for bridges. There is a gap to allow for temperature related expansions and contractions. Sometimes you drive over bridges and roadways where this movement is constricted and you might notice a bumpy ride. Engineers can predict the variation of structural length based on span lengths and leave the necessary gaps.....btw, NICE QUESTION:)</span>
