A force of 15 N is applied to a spring, causing it to stretch 0. 3 m. What is the spring constant for this particular spring? N/
1 answer:
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Answer:
In the vertical direction the acting forces are the normal force and the weight of the bobsleder plus the sled. In the horizontal direction the acting force is the friciton force.
Explanation:
Hi there!
Please, see the attached figure for a graphic representation of the forces acting on the sled after the bobsleder jumped in.
In the vertical direction, the acting forces are the normal force (N) and the weight of the sled plus the bobsledder (W).
Since the sled is not being accelerated in the vertical direction, the sum of forces in that direction is zero:
∑Fy = W + N = 0 ⇒ W = N
The weight is calculated as follows:
W = (mb + ms) · g
Where:
mb = mass of the bobsleder.
ms = mass of the sled.
g = acceleration due to gravity.
In the horizontal direction the only acting force is the friction force (Fr). The friction force is calculated a follows:
Fr = N · μ
Where:
N = normal force.
μ = kinetic friction coefficient.
Since N = W = (mb + ms) · g
Fr = (mb + ms) · g · μ
If we want to find the acceleration of the sled after the bobsleder jumps in, we can apply Newton's second law:
∑F = m · a
Where "a" is the acceleration and "m" is the mass of the object (in this case, the mass of bobsleder plus the mass of the sled).
∑F = Fr = (mb + ms) · g · μ = (mb + ms) · a
(mb + ms) · g · μ = (mb + ms) · a
Solving for "a":
g · μ = a
a) Their angular speeds are the same
b) Andrea's tangential speed is twice the value of Chuck's tangential speed
Explanation:
a)
The angular speed of Andrea and Chuck is the same.
Let's call the angular speed at which the merry-go-round is rotating. We know that the angular speed is defined as:
where
is the angular displacement covered in one revolution
T is the period of revolution
The merry go round is a rigid body, so all its point cover the same angular displacement in the same time: this means that it doesn't matter where Andrea and Chuck are located along the merry-go-round, their angular speed will still be the same.
b)
For an object in circular motion, the tangential speed is given by
where
is the angular speed
r is the distance from the centre of rotation
Here let's call the distance at which Chuck is rotating, so his tangential speed is
Now we know that Andrea is rotating twice as far from the centre, so at a distance of
So his tangential speed is
So, Andrea's tangential speed is twice the value of Chuck's tangential speed.
Learn more about circular motion:
#LearnwithBrainly
Answer:
The charge on the capacitor had increased
Explanation:
The expression for the capacitance of an air-filled parallel-plate capacitor is as follows as;
Here, C is the capacitance, is the permittivity of free space, A is the area and d is the distance between the parallel plate capacitor.
When a slab of dielectric material is placed between the plates of the capacitor then the expression for the capacitance is as follows;
Here, K is the dielectric constant.
In the given problem, a slab is inserted between the plates of the capacitor then the capacitance of the capacitor will increase in this case. Therefore, the option (a) is true.
The expression for the charge stored in the capacitor is as;
Q= CV
Here, Q is the charge and V is the potential.
The charge will also increase in this case as the charge stored in the capacitor is directly proportional to the capacitance. Therefore, the option (d) is not true.
The expression for the energy stored in the capacitor is as follows;
The voltage is constant in the given problem but the capacitance increases then the energy stored in the capacitor will increase. Therefore, the option (b) is not true.
The voltage across the capacitor will remain same as the capacitor is still connected to the battery. Therefore, the option (c) is not true.
Therefore, only option (a) is true.