Answer:
4.384 * 10^13
Explanation:
Given the expression :
[(6.67 * 10^-11) * (1.99 * 10^30)] ÷ [(1.74*10^3)*(1.74*10^3)]
Applying the laws of indices 
[(6.67 * 1.99) *10^(-11 + 30)] ÷ [(1.74 * 1.74) * 10^3+3]
13.2733 * 10^19 ÷ 3.0276 * 10^6
(13.2733 / 3.0276) * 10^(19 - 6)
4.3840996 * 10^13
= 4.384 * 10^13
 
        
             
        
        
        
The elastic potential energy of a spring is given by

where k is the spring's constant and x is the displacement with respect to the relaxed position of the spring.
The work done by the spring is the negative of the potential energy difference between the final and initial condition of the spring:

In our problem, initially the spring is uncompressed, so 

. Therefore, the work done by the spring when it is compressed until 

 is

And this value is actually negative, because the box is responsible for the spring's compression, so the work is done by the box.
 
        
        
        
A. is the answer for this question
        
             
        
        
        
Change in thermal energy not always cause it's temperature change. It is the situation when water reaches either at 0 C or 100 C then thermal energy doesn't cause change in temperature instead it changes the state of matter.
In short, Your Answer would be "True"
Hope this helps! 
        
                    
             
        
        
        
Answer:
 a = 17.68 m/s²
Explanation:
given,
length of the string, L = 0.8 m
angle made with vertical, θ = 61°
time to complete 1 rev, t = 1.25 s
radial acceleration = ?
first we have to calculate the radius of the circle
  R = L sin θ
  R = 0.8 x sin 61°
  R = 0.7 m
now, calculating at the angular velocity 
 
 
   ω = 5.026 rad/s
now, radial acceleration
  a = r ω²
  a = 0.7 x 5.026²
  a = 17.68 m/s²
hence, the radial acceleration of the ball is equal to 17.68 rad/s²