Answer:
a) 
b) 
Explanation:
Let's find the radius of the circumference first. We know that bob follows a circular path of circumference 0.94 m, it means that the perimeter is 0.94 m.
The perimeter of a circunference is:


Now, we need to find the angle of the pendulum from vertical.


Let's apply Newton's second law to find the tension.

We use centripetal acceleration here, because we have a circular motion.
The vertical equation of motion will be:
(1)
The horizontal equation of motion will be:
(2)
a) We can find T usinf the equation (1):

We can find the angular velocity (ω) from the equation (2):

b) We know that the period is T=2π/ω, therefore:

I hope it helps you!
Answer:
(a) 1000 N/C
Explanation:
Kinetic energy of electron, K = 1.6 x 10^-17 J
distance, d = 10 cm = 0.1 m
Let the potential difference is V and the electric field is E.
(a) The relation between the kinetic energy and the potential difference is
K = e V
V = K / e
Where, e be the electronic charge = 1.6 x 10^-19 C
V = 
V = 100 V
The relation between the electric field and the potential difference is given by
V = E x d
100 = E x 0.1
E = 1000 N/C
(b) The force acting on the electron, F = q E
where q be the charge on electron
So, F = -e x E
It means the direction of electric field and the force are both opposite to each other.
The direction of electric field and the force on electron is shown in the diagram.
Answer:
60
Explanation:
Translation -
A book weighing 12 N is balanced on a table. Knowing that the static friction coefficient is 0.5, how much is the friction force worth?
Friction force is
f = u * n
f = 0.5 * 12N
f = 60
Constant speed along the inclined surface = 30 m / 4 s = 7.5 m/s
Vertical speed = inclined speed * sin(45) = 7.5 *√2 / 2 = 5.3 m/s
Answer: 5.3 m/s