Answer:
Explanation:
Given
Initial velocity of ball 
height of window 
Using Equation of motion
where u=initial velocity
t=time
a=acceleration
As ball is already is at a height of 20 m so
(b)highest point is obtained at v=0
where
v=final velocity
u=initial velocity
a=acceleration
s=displacement
Highest Point will be 
(c)Time taken when the ball hit the ground i.e. at Y=0
impact velocity 
The electrical force is greater.
I'm not going to look it up and work it out right now,
but it seems to me that the electrical force is bigger
by a factor of something like 10⁴⁰ . That's a lot !
Answer:
Lindsey biked 45 miles for 3 hours at 15 mph and walked 8 miles for 2 hours at 4 mph.
Explanation:
Speed = distance/time
Let the distance that Lindsey biked through be x miles and the time it took her to bike through that distance be t hours
Then, the rest of the distance that she walked is (53 - x) miles
And the time she spent walking that distance = (5 - t) hours
Her biking speed = 15 mph = 15 miles/hour
Speed = distance/time
15 = x/t
x = 15 t (eqn 1)
Her walking speed = 4 mph = 4 miles/hour
4 = (53 - x)/(5 - t)
53 - x = 4 (5 - t)
53 - x = 20 - 4t (eqn 2)
Substitute for X in (eqn 2)
53 - 15t = 20 - 4t
15t - 4t = 53 - 20
11t = 33
t = 3 hours
x = 15t = 15 × 3 = 45 miles.
(53 - x) = 53 - 45 = 8 miles
(5 - t) = 5 - 3 = 2 hours
So, it becomes evident that Lindsey biked 45 miles for 3 hours at 15 mph and walked 8 miles for 2 hours at 4 mph.
B. Unless you add more water molecules or you add a new substance, the mass should stay the same no matter what.
