Answer:
1) Potential energy (gravitation)
2)Potential energy
3)Kinetic energy
4) Kinetic energy
5)Potential energy
6)Kinectic energy
7)Potential energy (elastic)
Hope it helps
 
        
             
        
        
        
Answer:
Q (heat) = S * m * (T2 - T1)  where Q is heat gained (loss), S the specific heat capacity of the substance and T2, T1 are the final and initial temps
Q = .215 cal  / (g deg C) * 5 g * (20 - 80) deg C = -64.5 cal
Since the question specifies the heat emitted, then  64.5 cal is the 
heat emitted (loss).
 
        
             
        
        
        
Answer:
(a) 

(b)
1120 N
Explanation:
Change in velocity,  is given by subtracting the initial velocity from the final velocity and expressed as
 is given by subtracting the initial velocity from the final velocity and expressed as 
Where v represent the velocity and subscripts f and i represent final and initial respectively. Since the ball finally comes to rest, its final velocity is zero. Substituting 0 for final velocity and the given figure of 8 m/s for initial velocity then the change in velocity is given by
 
To find  then we substitute 7 kg for m and -8 m/s for
 then we substitute 7 kg for m and -8 m/s for  therefore
 therefore 
(b)
The impact force, F is given as the product of mass and acceleration. Here, acceleration is given by dividing the change in velocity by time ie

Substituting t with 0.05 s then 
Since F=ma then substituting m with 7 Kg we get that F=7*-160=-1120 N
Therefore, the impact force is equivalent to 1120 N
 
        
             
        
        
        
Magnetic field describea magnet's ability to act at a distance
        
                    
             
        
        
        
Answer:
Tension = 0.012 N
Explanation:
If the black widow spider is hanging vertically motionless from the ceiling above. Then, the weight of the spider must be balancing the tension in the spider web. Therefore,
Tension = Weight
Tension = mg
where,
m = mass of spider = 1.27 g = 0.00127 kg
g = acceleration due to gravity = 9.8 m/s²
Therefore,
Tension = (0.00127 kg)(9.8 m/s²)
<u>Tension = 0.012 N</u>