The work done is the product between the intensity of the force applied F, the amount of the displacement d of the book and the cosine of the angle

between the direction of the force and the direction of the displacement:

In our problem, the student is lifting the book, so he is applying a force directed upward, and the book is moving upward, so F and d are parallel and therefore the angle is zero, so

Therefore, the work done is
Answer:
The amount of charge the space shuttle collects is -1.224nC
Explanation:
The magnitude of Electric potential is given as;
V = kq/r
where;
V is the electric potential in volts
k is coulomb's constant
r is the radius of the sphere or distance moved by the charge
given; V = -1.1 V, k = 8.99 x 10⁹ Nm²/C², r = 10m
Substituting this values in the above equation, we estimate the amount of charge space shuttle collects.
q = (V*r)/k
q = (-1.1 *10)/(8.99 x 10⁹ )
q = -1.224 X 10⁻⁹ C
q = -1.224nC
Therefore, the amount of charge the space shuttle collects is -1.224nC
<h2>Snow starts to move down the mountain </h2>
The energy which is due to position is potential energy. So when the snow is lying on the mountain. It possess potential energy but when suddenly, it starts to move down the mountain, the potential energy is converted into the kinetic energy. Yet some force is exerting on the snow to stop the smooth flow of snow through mountains.
This example of frictional force may be due to presence of rough surface or stones. Generally, there are four types of friction as static, rolling, sliding and fluid friction. Though in this case when snow is lying it possess static friction, when flows then it possesses sliding and fluid friction both.
Answer:
halved
Explanation:
The velocity of the a wave is obtained by multiplying the frequency and wavelength.

Where
v = Velocity
f = Frequency
= Wavelength
The velocity here is constant. So, if the frequency is doubled the wavelength is halved.
Answer: When the electric field due to one is a maximum, the electric field due to the other is also a maximum, and this relation is maintained as time passes. They alternatively reinforce and cancel each other.
Explanation:
In a wave, the phase, is an arbitrary time reference, used to locate a given point of the wave in time, within a cycle.
Two waves can travel at the same speed, or even have the same wavelength, but this is not enough to be sure that at a given point in time, both waves will be in their maximum, as it only can be determined from the phase of the waves.
So, only when the waves reach at the same point in time at the same amplitude, we can say that they arrive in phase, in a constructive interference.