The ball can't reach the speed of 20 m/s in two seconds, unless you THROW it down from the window with a little bit of initial speed. If you just drop it, then the highest speed it can have after two seconds is 19.6 m/s .
If an object starts from rest and its speed after 2 seconds is 20 m/s, then its acceleration is 20/2 = 10 m/s^2 .
(Gravity on Earth is only 9.8 m/s^2.)
Answer:
Acceleration due to gravity, 
Explanation:
It is given that,
Mass of Pluto, 
Distance between Neptune and Pluto, 
The force of gravity is balanced by the gravitational force between Neptune and Pluto. It is given by :
So, the acceleration due to gravity at Neptune due to Pluto is 
. Hence, this is the required solution.
Answer:
<em>1.01 W/m</em>
Explanation:
diameter of the pipe d = 30 mm = 0.03 m
radius of the pipe r = d/2 = 0.015 m
external air temperature Ta = 20 °C
temperature of pipe wall Tw = 150 °C
convection coefficient at outer tube surface h = 11 W/m^2-K
From the above,<em> we assumed that the pipe wall and the oil are in thermal equilibrium</em>.
area of the pipe per unit length A = 
= 
m^2/m
convectional heat loss Q = Ah(Tw - Ta)
Q = 7.069 x 10^-4 x 11 x (150 - 20)
Q = 7.069 x 10^-4 x 11 x 130 = <em>1.01 W/m</em>
Find the number of hours by dividing the distance by mph. The number of hours will be to the left of the decimal point:
250 miles / 65 mph
= 3.846153846
= 3 hours
2) Find the number of minutes by multiplying what is remaining from step 1 by 60 minutes. The minutes will be to the left of the decimal point:
0.846153846 x 60
= 50.76923076
= 50 minutes
3) Find the number of seconds by multiplying what is remaining from step 2 by 60 seconds. The seconds will be to the left of the decimal point:
0.76923076 x 60
= 46.1538456
= 46 seconds
So 3 hours 50 mins and 46 seconds
Work done = M x g x h
M = Mass of the body in Kg
g = Acceleration due to gravity
h - height of displacement
Work done = (M x g) x h
= 50 N x 1.5 m
= 75 J
