Answer:
A. <u>The water decreases the friction between the floor and the feet </u>
Explanation: Think about it like this, when your in the shower and water is on your skin, you can scrub it fluidly, but when the water dries in your towel, there is more friction when your rub your skin, this is because the molecules in water aren't as compact as solids, so anything acting against it, is most likely to disperse from it.
I can think of two of them:
-- carbon monoxide
-- black soot
From what I can see it's D, I did this by simply examining the other answers and seeing that they are beneficial, so, from that information, this one must not be.
Answer:
Explanation:
100 mph = 100 x 1760 x 3 / ( 60 x 60 )
= 146.67 ft / s
70 mph = 70 x 1760 x 3 / ( 60 x 60 )
= 102.67 ft/s
Let mass of the ball = m .
The ball which was moving with a velocity of 146.67 ft/s is turned back by the action of force of bat on the ball and it moved in opposite direction with velocity of - 102.67 ft/s ( - ve sign due to reversed direction )
If m be the mass of ball
change in momentum = m x 146.67 - ( - m x 102.67 )
= m x 146.67 + m x 102.67
= 249.34 m
Change in momentum = impulse = force x time
Putting the given values
249.34 m = force x 1 x 10⁻³ ( time = 10⁻³ s )
force = 249.34 m x 10³ poundal .
Here m is mass of the ball in lb .
