Chris is about to do an experiment to measure the density of water at several temperatures. His teacher has him prepare and sign
2 answers:
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Answer:
Option B, 93 cm
Explanation:
An diagram of the seed's motion is attached to this solution.
This is very close to a projectile motion question. And the quantity to be calculated, how far along the grant a seed released would travel is called the Range.
And this would be obtained from the equations of motion,
First of, the height of the plant is related to some quantities of the motion with this relation.
H = u(y) t + 0.5g(t^2)
U(y) = initial vertical component of velocity = 0 m/s, H = height at which motion began, = 20cm = 0.2 m
That means t = √(2H/g)
The horizontal distance covered, R,
R = u(x) t + 0.5g(t^2) = u(x) t (the second part of the equation goes to zero as the vertical component of the acceleration of this motion is 0)
(substituting the t = √(2H/g) derived from above
R = u(x) √(2H/g)
Where u(x) = the initial horizontal component of the bomb's velocity = maximum initial speed, that is, 4.6 m/s, H = vertical height at which the seed was released = 20 cm = 0.2 m, g = acceleration due to gravity = 9.8 m/s2
R = 4.6 √(2×0.2/9.8) = 0.929 m = 0.93 m = 93 cm. Option B.
QED!
Answer:
10.4 m/s
Explanation:
The problem can be solved by using the following SUVAT equation:
where
v is the final velocity
u is the initial velocity
a is the acceleration
t is the time
For the diver in the problem, we have:
is the initial velocity (positive because it is upward)
is the acceleration of gravity (negative because it is downward)
By substituting t = 1.7 s, we find the velocity when the diver reaches the water:
And the negative sign means that the direction is downward: so, the speed is 10.4 m/s.
a) Average velocity: 2.8 m/s
b) Average velocity: 5.2 m/s
c) Average velocity: 7.6 m/s
Explanation:
a)
The position of the car as a function of time t is given by
where
The average velocity is given by the ratio between the displacement and the time taken:
The position at t = 0 is:
The position at t = 2.00 s is:
So the displacement is
The time interval is
And so, the average velocity in this interval is
b)
The position at t = 0 is:
While the position at t = 4.00 s is:
So the displacement is
The time interval is
So the average velocity here is
c)
The position at t = 2 s is:
While the position at t = 4 s is:
So the displacement is
While the time interval is
So the average velocity is
Learn more about average velocity:
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Electric charge on the plastic cube:
Explanation:
The electric potential around a charged sphere (such as the Van der Graaf) generator is given by
where
k is the Coulomb's constant
Q is the charge on the sphere
r is the distance from the centre of the sphere
Here we have:
V = 200,000 V on the surface of the sphere, so at r = 12.0 cm
We need to find the voltage V' at 2.0 cm from the edge of the sphere, so at
r' = 12.0 + 2.0 = 14.0 cm
Since the voltage is inversely proportional to r, we can use:
This is the potential at the location of the plastic cube.
Now we can use the law of conservation of energy, which states that the initial electric potential energy of the cube is totally converted into kinetic energy when the plastic cube is at infinite distance from the generator. So we can write:
where:
q is the charge on the plastic cube
V' is the potential at the location of the cube
m = 5.0 g = 0.005 kg is the mass of the cube
v = 3.0 m/s is the final speed of the cube
Solving for q, we find the charge on the cube:
Learn more about electric fields:
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