Velocity is the speed of something in a given direction.
Vector is a quantity having direction as well as magnitude
Answer:
The frictional force points up the incline.
Explanation:
It is given that, the crate is at rest on the incline. We know that the forces acting on the crate are force of gravity, normal and the force of friction. We know that the frictional force is the force that opposes the motion of an object.
In this case the crate is at rest. The crate will have static friction, that points up the incline.
So, the correct option is (A) "the frictional force points up the incline".
Answer:
The main effect of radiofrequency electromagnetic fields is heating of body tissues.
Explanation:
Image result for How do electromagnetic waves affect you?
At low frequencies, external electric and magnetic fields induce small circulating currents within the body. ... The main effect of radiofrequency electromagnetic fields is heating of body tissues. There is no doubt that short-term exposure to very high levels of electromagnetic fields can be harmful to health.
Answer: 299,427.84 J, 99,809.28 W
Explanation: we will assume the acceleration of the body to be constant, hence newton's laws of motion is applicable.
From the question
Force (f) = 75 N
Mass of object (m) = 6kg
Initial velocity (u) = 20 m/s
Final velocity (v) = 58 m/s
Time taken (t) = 3s
Recall that
F = ma
75 = 6a
a = 75/6 = 12. 5 m/s²
We need to get the distance before we can get the work done.
Recall that v² = u² + 2as, where s = distance covered
56² = 20² + 2(12.5)s
56² - 20² = 25s
2736 = 25s
s = 2736/ 25 = 109.44m
Work done = force × distance
Work done = 75 × 109.44 = 299,427.84 j
Power = work done / time
Power = 299,427.84 / 3
Power = 99,809.28 W
