There are three forces acting on the book.
1. Force due to gravity
2. Force exerted downward by the hamster
3. Normal Force in reaction to the downward forces
Since the book is not moving, the net force is zero. The summation of all forces must be zero. Then we could find the normal force which is unknown (denoted as x).
∑F = -(4 kg)(9.81 m/s2) - 3 N + x =0
∑F = -39.24 N - 3N + x =0
x = 42 N
Therefore, the normal force is 42 N.
Answer:
C: Variation in the value of g as the pendulum bob moves along its arc.
Explanation:
The formula for period of a simple pendulum is given by;
T = 2π√(L/g)
Where;
L is length
g is acceleration due to gravity
Now, from this period equation, it is clear that the only thing that can affect the period of a simple pendulum are changes to its length and acceleration due to gravity.
Looking at the options, the only one that talks about either the length or gravity as being potential causes of the error is option C
Answer:
electrons
Explanation:
The magnitude of the electric field outside an electrically charged sphere is given by the equation

where
k is the Coulomb's constant
Q is the charge stored on the sphere
r is the distance (from the centre of the sphere) at which the field is calculated
In this problem, the cloud is assumed to be a charged sphere, so we have:
is the maximum electric field strength tolerated by the air before breakdown occurs
is the radius of the sphere
Re-arranging the equation for Q, we find the maximum charge that can be stored on the cloud:

Assuming that the cloud is negatively charged, then

And since the charge of one electron is

The number of excess electrons on the cloud is

I think the answer you’re looking for is
D)
-I hope this helps! Enjoy the rest of your day