The term used is " WORK".
I'm really sorry it's not one of the choices.
 
        
                    
             
        
        
        
Answer:
1.68 s
Explanation:
From newton's equation of motion,
a = (v-u)/t.................................. Equation 1
Making t the subject of the equation
t =(v-u)g............................. Equation 2
Where t = time taken for the bowling pin to reach the maximum height, v = final velocity bowling pin, u = initial velocity of the bowling pin, g = acceleration due to gravity.
Note: Taking upward to be negative and down ward to be positive,
Given: v = 0 m/s ( at the maximum height), u = 8.20 m/s, g = -9.8 m/s²
t = (0-8.20)/-9.8
t = -8.20/-9.8
t = 0.84 s.
But,
T = 2t
Where T = time taken for the bowling pin to return to the juggler's hand.
T = 2(0.84)
T = 1.68 s.
T = 1.68 s
 
        
             
        
        
        
Answer:
k = 49 N/m
Explanation:
Given that,
Mass, m = 250 g = 0.25 kg
When the mass is attached to the end of the spring, it elongates 5 cm or 0.05 m. We need to find the spring constant. Let it is k.
The force due to mass is balanced by its weight as follows :
mg=kx

So, the spring constant of the spring is 49 N/m.
 
        
             
        
        
        
Answer:
D.) 1m/s
Explanation:
Assume the initial angle of the swing is 12.8 degree with respect to the vertical. We can calculate the vertical distance from this initial point to the lowest point by first calculate the vertical distance from this point the the pivot point:

where L is the pendulum length
The vertical distance from the lowest point to the pivot point  is the pendulum length 2m
 is the pendulum length 2m
this means the vertical distance from this initial point to the lowest point is simply:

As the pendulum travel (vertically) from the initial point to the bottom point, its potential energy is converted to kinetic energy:


where m is the mass of the pendulum, g  = 10 m/s2 is the constant gravitational acceleration, h = 0.05 is the vertical it travels, v is the pendulum velocity at the bottom, which we are trying to solve for.
The m on both sides of the equation cancel out


so D is the correct answer
 
        
             
        
        
        
Answer:
Main Difference Between Mechanical and Electromagnetic waves
A wave is composed of some kind of disturbance that propagates. We can classify waves into many different types based on their properties. One of the properties of the waves depends on whether they need a medium to propagate or not. The primary difference between electromagnetic and mechanical waves is also based on this property. Mechanical waves need a medium, while electromagnetic waves do not need a medium to propagate. Electromagnetic waves can travel through a vacuum. The other differences between mechanical and electromagnetic waves are given below:
Electromagnetic waves can travel through a vacuum, that is an empty space, whereas mechanical waves cannot. They need a medium to travel such as water or air. Ripples in a pond are an example of mechanical waves whereas electromagnetic waves include light and radio signals, which can travel through the vacuum of space.
Mechanical waves can be classed as elastic waves because their transmission depends on the medium's (water, air etc.) elastic properties.
Electromagnetic waves are caused because of the varying magnetic and electric fields. They are produced by the vibration of the charged particles.
Because of these differences, the speed of each type of wave varies significantly. Electromagnetic waves travel at the speed of light but mechanical waves are far slower.
                                                                             Have a wonderful day!
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