Answer: 0.8 m
Explanation:
In the vertical direction, the speed is zero, u = 0.
Distance covered in the vertical direction, s = 0.75 m.
The book would fall with acceleration due to gravity in the vertical direction, a = g = 9.8 m/s²
From the equation of motion,
s = u t + 0.5 a t²
Substituting the above values, we will find out the time taken for the book to hit the ground.
⇒0.75 m=0+0.5×9.8 m/s²×t²
⇒t = √0.153 = 0.39 s ≈ 0.40 s
Now, the horizontal distance covered,
d = v×t ⇒d= 2.0 m/s × 0.40 s =0.8 m
Hence, the book falls 0.8 m away from the desk.
Answer: D. The force and displacement are in the same direction.
Explanation:
The Work 
done by a Force 
refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path with distance 
.
Work is a scalar magnitude, and its unit in the International System of Units is the Joule (like energy).
Now, when the applied force is constant and the direction of the force and the direction of the displacement are <u>parallel</u>, the equation to calculate it is:
(1)
When they are not parallel, both directions form an angle, let's call it 
. In that case the expression to calculate the Work is:
(2)
When the force and displacement are perpendicular to each other,
and <u>no work is done</u>.
Answer:
a) equal 1, b) less than 1
Explanation:
a) the electric force is given by
Fe = q E
The charge of the electron and proton has the same value, that of the proton is positive and that of the electron is negative
Proton
Fp = qE
Electron
Fe = - q E
Fp / Fe = -1
If we do not take into account the sign the relationship is equal to one (1)
b) to calculate the force we use Newton's second law
F = ma
qE = m a
a = q E / m
The mass of the proton much greater than the mass of the electron
ap = q E / 
ae = - q E / 
ap / ae = /
= /1600 =1/1600
It is much smaller than 1
Answer:
The turning effect of a force is known as the moment. It is the product of the force multiplied by the perpendicular distance from the line of action of the force to the pivot or point where the object will turn. When undoing a nut fastened to a screw by hand one realises that the amount of force required is a lot greater than when undoing the same nut using a spanner.
Explanation:
When a body strictly moves on a curve, it's velocity at a point is tangential to the curve at that point.
Centripetal acceleration is the acceleration that a body experiences by the virtue of change in it's tangential velocity. It is directed towards the centre and mathematically is v^2/R where v is the speed at the instant.
So, 18 = v^2/R
v^2 = 504
v = 6√14
