Explanation:
Fgravity = G*(mass1*mass2)/D²
so, if you double one of the masses, what does that do to our equation ?
Fgravitynew = G*(2*mass1*mass2)/D²
due to the commutative property of multiplication
Fgravitynew = 2* G*(mass1*mass2)/D² = 2* Fgravity
so, the correct answer will be 2×45 = 90 units.
Answer:
It takes her 3.409 seconds to make a full stop.
Explanation:
The time it takes to make a full stop can be determined by the equation of velocity for a Uniformly Accelerated Rectilinear Motion:
(1)
Where 
is the final velocity, 
is the initial velocity, a is the acceleration and t is the time.
Equation (1) can be rewritten in terms of t:
(2)
For this particular case the final velocity will be equal to zero (
):
So it takes her 3.409 seconds to make a full stop.
How much gravitational potential energy does the block have
when it gets to the top of the ramp ?
(weight) x (height) = (15 N) x (0.2 m) = 3 Joules .
If there were no friction, you would only need to do 3 Joules of work
to lift the block from the bottom to the top.
But the question says you actually have to do 4 Joules of work
to get the job done.
Friction stole one of your Joules along the way.
Choice-4 is not the correct one.
Choice-1 is the correct one.
===========================
Notice that the mass of the block is NOT 15 kg , and you
don't have to worry about gravity to answer this question.
The formula for potential energy is (m)·(g)·(h) .
But (m·g) is just the WEIGHT, and the formula
is actually (weight)·(height).
The question GIVES us the weight of the block . . . 15 N .
So the potential energy at the top is just (15N)·(0.2m) = 3 Joules.
An object in motion tends to stay in motion an oject at rest stays at rest.
Surface Tension. Molecules on the surface experience cohesion, this means molecules that are the same material stick together.
