Answer:
The answer is D.
Explanation:
Average speed involve just distance and time but average velocity includes displacement and time.
(Correct me if I am wrong)
Answer:
693.685 N
Explanation:
t = Time taken
u = Initial velocity = 27 m/s
v = Final velocity
s = Displacement = 578 m
a = Acceleration
m = Mass
Equation of motion
Force
F = ma
Magnitude of braking force required to stop the car is 693.685 N
Answer:
b) there must be a component of force parallel to the motion of the object.
Explanation:
We know that work done on a body by an external force is calculated by the formula given below:
W = F.d = Fd Cos θ
where,
W = Work Done by the force on the body
F = Magnitude of force
d = displacement of the body
θ = The angle between the direction of motion of the body and the force applied
It is clear from the formula of the work done, that "F Cosθ" represents the component of the force, that is acting in the direction of motion of the object or parallel to the direction of motion of the object. So, if there is no component of force parallel to motion of object, then this factor will become zero. As a result, the work done will also be zero.
Therefore, the correct option will be:
b) <u>there must be a component of force parallel to the motion of object.</u>
Answer:
Sound waves in liquids and gases involve alternating compression and rarefaction of material along a line defining the direction of propagation of the wave. These waves are known as longitudinal waves, and of course exist only in a medium that can be compressed and rarefied. In solids, sound energy also produces longitudinal waves, but it can also produce transverse waves, in which compression and rarefaction occurs perpendicular to the direction of propagation. These two waves propagate at different speeds, a phenomenon that is most noticeable in earthquakes. The first wave gives notice that the quake is coming, the second one does the damage. The time between the two tells you how far away the epicenter is. In water there is another kind of wave, called a gravity wave, the kind you see at the beach. All of these wave require a medium. There is no sound in a vacuum.
