Answer:
2491.23 kg/m³
Explanation:
From Archimedes principle,
R.d = weight of object in air/ upthrust in water = density of the object/density of water
⇒ W/U = D/D' ....................... Equation 1
Where W = weight of the ceramic statue, U = upthrust of the ceramic statue in water, D = density of the ceramic statue, D' = density of water.
Making D the subject of the equation,
D = D'(W/U).................... Equation 2
Given: W = 28.4 N, U = lost in weight = weight in air- weight in water
U = 28.4 - 17.0 = 11.4 N,
Constant: D' = 1000 kg/m³.
Substitute into equation 2,
D = 100(28.4/11.4)
D = 2491.23 kg/m³
Hence the density of the ceramic statue = 2491.23 kg/m³
This is another one of those muddy misleading questions, followed by
a muddy group of choices from which an answer must be selected.
a). is absurd. There's no such thing as a "balanced force", only
a balanced group of forces.
b). is probably the choice the question is aiming for.
c). is not so. The engines of an airplane do plenty of work lifting the plane
off the ground, although the force of the engines is never directed upward.
d). is really awkward. The object's motion is almost never the cause of the force.
The force is almost always the cause of the object's motion.
Now for the big 800-lb gorilla in the room: No moving object needs to be involved
in order for energy to be flowing or work to be getting done.
-- A radio wave radiates through space. Straighten out a wire coat-hanger and
stick it up in the air where the radio wave can pass by it. Electrical current flows
through the wire, and you can drain the electrical energy out the bottom of it.
-- A light bulb is shining. Some distance away, something it's shining on
gets warm, because of the heat energy that has shot across to it from the
light bulb and soaked into it.
-- A lightning bolt jumps from the ground to a passing cloud. Or, if you feel
more comfortable with it, a lightning bolt jumps from a cloud to the ground.
It doesn't matter. Either way, there's enough energy splashing around to
ignite houses, zap TVs and computers, melt concrete, vaporize water, and
light up a city. Although nothing is moving.
Answer:
A) being influenced by equal amounts of gravity and air resistance.
Explanation:
B) slowing down because of an unbalanced force of air resistance.
False - if it was slowing down, then the velocity would go down.
D) on the ground and is not falling anymore.
False - This would be mistaken as the answer but it is not because if the person is not falling anymore the horizontal line should be at the x-axis, meaning that there is no more velocity.
C) accelerating because of an unbalanced force of gravity.
False - The line would otherwise be going up or down.
Answer:
d = 1.954 Km
Explanation:
given,
total distance, D = 2.5 Km
in stretch A to B =
speed = 99 Km/h = 99 x 0.278 = 27.22 m/s time =t
in stretch B to C
time = 3.4 s
In stretch C to D
speed = 48 Km/h = 48 x 0.278 = 13.34 m/s time =t
we know,
distance = speed x time
distance of BC
using equation of motion
v = u + a t
27.22 = 13.34 - a x 3.4
a = 4.08 m/s²
uniform deceleration is equal to 4.08 m/s²
distance traveled in BC
s = 68.94 m
3000 = 27.5 t + 68.94 + 13.33 t
40.83 t = 2931.06
t = 71.79 s
distance travel in AB
distance = s x t
d = 27.22 x 71.79
d = 1954 m
d = 1.954 Km
distance between A and B is equal to 1.954 Km.
