I took the test and this is the answer key showing I got it right..
Hope this helps!
Neither object will float in water.
They both have densities greater than 1.0 g/cm³,
so both will sink to the bottom of the beaker.
Like rocks.
R = radius of the loop
m = mass of the roller coaster car
for looping the loop critical speed at the top is given as
v₀ = critical speed at the top = sqrt(2gR)
given that :
v = speed of crossing at the top = 2 v₀ = 2 sqrt(2gR)
F = normal force at the top in downward direction
W = weight in downward direction = mg
force equation at the top is given as
F + W = m v²/R
F + mg = m (2 sqrt(2gR))²/R
F + mg = m (4 x 2 gR)/R
F + mg = m (8gR)/R
F + mg = 8 mg
F = 7 mg
F/(mg) = 7
so the ratio comes out to be 7:1
-ZERO- No 17.6 pound Earth-bound cat is going to be able to jump to the top of a 6 feet 7 inch bookshelf unassisted! Someone should call the SPCA on the writer of this textbook question ;-)
Assuming that this overweight cat is content being placed in such a lofty position, your professor probably wants the answer of <u>156.8 Joules</u>
Mass x Acceleration of Gravity (on Earth) x elevation = Potential Energy
8 Kg x 9.8 m/s2 x 2 m = 156.8 J
T=10000N (g=10 <span>m<span>s2</span></span>)
Explanation:
If elevator is hanging from the cable a non contact force 'mg' is acting on it in downward direction .If the is cable is able to hold the lift in air then it would require force greater than or equal to force of gravitation i.e, 'mg' in opposite direction to prevent it from falling and counter balance force of gravitation i.e,'mg'. Now if force applied by cable is greater than 'mg' it will move up with some initial acceleration.But as lift is rest only force required will be equal to'mg'.