Answer:
The work done on the system is -616 kJ
Explanation:
Given;
Quantity of heat absorbed by the system, Q = 767 kJ
change in the internal energy of the system, ΔU = +151 kJ
Apply the first law of thermodynamics;
ΔU = W + Q
Where;
ΔU  is the change in internal energy
W is the work done 
Q is the heat gained
W = ΔU  - Q
W = 151 - 767
W = -616 kJ (The negative sign indicates that the work is done on the system)
Therefore, the work done on the system is -616 kJ
 
        
             
        
        
        
Answer:
40m/s
Explanation:
The horizontal component of velocity remains constant because there are no external forces in that direction
By applying motion equations, V= U+ at
where , 
- v - final velocity
 - u - initial velocity
 - a-acceleration
 - t - time
 
v = u +at
 As no force act on the ball ( we neglect air resistance here) no acceleration is seen, 
So v = u = 40m/s
 
        
             
        
        
        
Answer:
5N
Explanation
convert grams to kg and multipy with 10 (.5 *10)=5N
 
        
             
        
        
        
Answer:
the size of the shadow will be smaller due to smaller hands
 
        
             
        
        
        
Answer:
90°
Explanation:
The angle will be 90° when momentum for a system can be conserved in one direction while not being conserved in another. 
The example can be 
If we apply force on an object horizontally in west direction, then as in other direction south or north we cannot apply the principal of momentum conservation.