Answer:
we learned that an object that is vibrating is acted upon by a restoring force. The restoring force causes the vibrating object to slow down as it moves away from the equilibrium position and to speed up as it approaches the equilibrium position. It is this restoring force that is responsible for the vibration. So what forces act upon a pendulum bob? And what is the restoring force for a pendulum? There are two dominant forces acting upon a pendulum bob at all times during the course of its motion. There is the force of gravity that acts downward upon the bob. It results from the Earth's mass attracting the mass of the bob. And there is a tension force acting upward and towards the pivot point of the pendulum. The tension force results from the string pulling upon the bob of the pendulum. In our discussion, we will ignore the influence of air resistance - a third force that always opposes the motion of the bob as it swings to and fro. The air resistance force is relatively weak compared to the two dominant forces.
The gravity force is highly predictable; it is always in the same direction (down) and always of the same magnitude - mass*9.8 N/kg. The tension force is considerably less predictable. Both its direction and its magnitude change as the bob swings to and fro. The direction of the tension force is always towards the pivot point. So as the bob swings to the left of its equilibrium position, the tension force is at an angle - directed upwards and to the right. And as the bob swings to the right of its equilibrium position, the tension is directed upwards and to the left. The diagram below depicts the direction of these two forces at five different positions over the course of the pendulum's path. 
that's what I know so far
 
        
             
        
        
        
I think its d. but im not sure
        
                    
             
        
        
        
Answer:


Explanation:
Given



See attachment
Required
Determine PCD and CPD
First, we need to calculate CPD
Since DPA is a straight line and CPA = 100;
We have that:
 --- angle on a straight theorem
 --- angle on a straight theorem
Substitute 100 for CPA

Subtract 100 from both sides


Next, we calculate PCD
We have that:
 --alternate angle
  --alternate angle
In triangle PCD
 --- angles in a triangle
 --- angles in a triangle
Where

So, we have:


Subtract 136 from both sides


 
        
             
        
        
        
Answer:
F = 3.20 N
Explanation:
Given:
Work done by child = 80.2 j
Distance that the car moves = 25.0 m
We need to find the force acting on the car.
Solution:
Using work done formula as.

Where:
W = Work done by any object.
F = Force (push or pull)
d = distance that the object moves.
Substitute  in work done formula.
 in work done formula.


F = 3.20 N
Therefore, force acting on the car F = 3.20 N