Answer:
a. Vf = 39.24 [m/s]
b. Vf = 31.24 [m/s]
c. Vf = 47.24 [m/s].
Explanation:
To solve this problem we can use the following equation of kinematics. We have to keep in mind that the gravitational acceleration acts downwards, therefore when the rock falls towards the abyss it has the same direction of the acceleration and that is why the gravitational acceleration has a positive sign in the equation.
where:
Vf = final velocity [m/s]
Vo = initial velocity = 0 (when the rock is dropped)
g = gravitational acceleration = 9.81 [m/s²]
t = time = 4 [s]
a.
![v_{f}=0+9.81*4\\v_{f}= 39.24 [m/s]](https://tex.z-dn.net/?f=v_%7Bf%7D%3D0%2B9.81%2A4%5C%5Cv_%7Bf%7D%3D%2039.24%20%5Bm%2Fs%5D)
b.
In this particular situation, the acceleration will be taken as negative because the gravity is pointing in the opposite direction of the movement of the rock.
![v_{f}=8-(9.81*4)\\v_{f}=-31.24[m/s]](https://tex.z-dn.net/?f=v_%7Bf%7D%3D8-%289.81%2A4%29%5C%5Cv_%7Bf%7D%3D-31.24%5Bm%2Fs%5D)
The negative sign in the answer tells us that the rock no longer moves up instead it does downwards when 4 seconds have passed.
c.
![v_{f}=8+(9.81*4)\\v_{f}=47.24[m/s]](https://tex.z-dn.net/?f=v_%7Bf%7D%3D8%2B%289.81%2A4%29%5C%5Cv_%7Bf%7D%3D47.24%5Bm%2Fs%5D)
Answer:
0.8m per second
Explanation:
we measure speed as distance over time
distance=8m
time=10s
therefore speed = 8/10
=0.8m per second
Answer:
option (D
Explanation:
Torque is given by
torque = N x i x A x B x sinФ
where, N is number of turns, A is area, b is the magnetic field and Ф be the angle between the area vector and the magnetic field vector, i be the current.
So, torque depends on the current.
option (D)
Answer:
C) T
Explanation:
= Mass attached to an ideal spring
= Amplitude of the motion
= Time period of oscillation
= Spring constant of the spring
= Amplitude of the motion
Time period of oscillation of the mass attached to the spring is given as
So we see that the time period does not depend on the amplitude. hence the period of oscillation remains the same.
You do the net force by subtracting the sides. The direction of the box is moving forward to the right by 10 N.
