Answer
given,
mass of the crate  = 53 Kg
force applied by the worker = 180 N
Angle made with the horizontal = 35°
crate moves = 2.9 m
a) The work done equals the force in the direction of the displacement, times the displacement
W = F_x ×d 
W = 180 cos 35° × 2.9
W = 427.6 J
b) A force that is perpendicular to the direction of the displacement does not do any work so work done by gravitational force is zero
c) Similarly for the normal force the work done will be zero. 
d) Total work done by the crate is equal to 427.6 J
 
        
             
        
        
        
A. electrons are negatively charged outside nucleus
        
                    
             
        
        
        
Answer:
Velocity of the car at the bottom of the slope: approximately  .
.
It would take approximately  for the car to travel from the top of the slope to the bottom.
 for the car to travel from the top of the slope to the bottom.
Explanation:
The time of the travel needs to be found. Hence, make use of the SUVAT equation that does not include time. 
- Let  denote the final velocity of the car. denote the final velocity of the car.
- Let  denote the initial velocity of the car. denote the initial velocity of the car.
- Let  denote the acceleration of the car. denote the acceleration of the car.
- Let  denote the distance that this car travelled. denote the distance that this car travelled.
 .
.
Given:
Rearrange the equation  and solve for
 and solve for  :
:
 .
.
Calculate the time required for reaching this speed from  at
 at  :
:
 .
.
 
        
             
        
        
        
<span>The star's main fuel during its lifetime is hydrogen. It is said that a star is composed of 97% hydrogen and 3% helium. Once the hydrogen of a star is gone, the star becomes old because it burns hydrogen during its lifetime.</span>