The longer you spend reading and thinking about this question,
the more defective it appears.
-- In each case, the amount of work done is determined by the strength
of
the force AND by the distance the skateboard rolls <em><u>while you're still
</u></em>
<em><u>applying the force</u>. </em>Without some more or different information, the total
distance the skateboard rolls may or may not tell how much work was done
to it.<em>
</em>
-- We know that the forces are equal, but we don't know anything about
how far each one rolled <em>while the force continued</em>. All we know is that
one force must have been removed.
-- If one skateboard moves a few feet and comes to a stop, then you
must have stopped pushing it at some time before it stopped, otherwise
it would have kept going.
-- How far did that one roll while you were still pushing it ?
-- Did you also stop pushing the other skateboard at some point, or
did you stick with that one?
-- Did each skateboard both roll the same distance while you continued pushing it ?
I don't think we know enough about the experimental set-up and methods
to decide which skateboard had more work done to it.
To solve this problem, we will get f and then we will use it to calculate the power.
So, for this farsighted person,
do = 25 cm and di = -80
Therefore:
1/f = (1/25) + (1/-80) = 0.00275 = 0.275 m
Power = 1/f = 1/0.275 = +3.6363 Diopeters.
This means that the lens is converging.
Answer:
Y component = 32.37
Explanation:
Given:
Angle of projection of the rocket is, 
Initial velocity of the rocket is, 
A vector at an angle
with the horizontal can be resolved into mutually perpendicular components; one along the horizontal direction and the other along the vertical direction.
If a vector 'A' makes angle
with the horizontal, then the horizontal and vertical components are given as:

Here, as the velocity is a vector quantity and makes an angle of 33.6 with the horizontal, its Y component is given as:

Plug in the given values and solve for
. This gives,

Therefore, the Y component of initial velocity is 32.37.
volume of balloon
= 4/3 T R3
= 4/3 x 3.14 x 6.953
= 1405.47 m3
uplift force
= volume of balloon x density of air x 9.8
= = 1405.47 x 1.29 x 9.8
= 1813.05 x 9.8 N
weight of helium gas
= volume of balloon x density of helium x
9.8
= 1405.47 x .179 x 9.8
= 251.58 x 9.8 N
Weight of other mass = 930 x 9.8 N Total weight acting downwards
= 251.58 x 9.8 +930 x 9.8
= 1181.58 x 9.8 N
If W be extra weight the uplift can balance
1181.58 × 9.8 + W × 9.8 = 1813.05 * 9.8
1181.58+W=1813.05
W= 631.47 kg
Answer:
24.07415 rpm
Explanation:
= Coefficient of friction = 0.63
v = Velocity
d = Diameter = 4.9 m
r = Radius = 
m = Mass
g = Acceleration due to gravity = 9.81 m/s²
Here the frictional force balances the rider's weight

The centripetal force balances the weight of the person

Velocity is given by

Converting to rpm

The minimum angular speed for which the ride is safe is 24.07415 rpm