When someone lifts a book from the ground, the work you use is positive. By lifting the book, you change it's energy and it's original place The book gains, kinectic energy.
Hope I helped.
 
 
        
             
        
        
        
Answer:
Part A: 16.1 V
Part B: 20.5 V
Part C: 21.5%
Explanation:
The voltmeter is in parallel with the 4.5-kΩ resistor and the combination is in series with the 6.5-kΩ resistor. The equivalent resistance of the parallel combination is given as


Part A
The voltmeter reading is the potential difference across the parallel combination. This is found by using the voltage-divider rule.

Part B
Without the voltmeter, the potential difference across the 4.5-kΩ resistor is found using the same rule as above:

Part C
The error in % is given by 

 
        
                    
             
        
        
        
The specific heat of a metal or any element or compound can be determined using the formula Cp = delta H / delta T / mass. delta pertains to change. That is change in enthalpy and change in temperature. From the given data, Cp is equal to 343 cal per (86-19) c per 55 grams. This is equal to 0.093 cal / g deg. Celsius
        
             
        
        
        
Answer:
The waves will increase in frequency
Explanation:
As the young girl moves her hand back and forth faster, it will be observed that number of back and forth motions increase every second. Also the distance between crest and trough of the wave (wavelength) will be reduced as she moves her hand back and forth faster. 
Frequency = number of turns (moves) per second
The waves will increase in frequency since there will be more number of back and forth motions in every second. 
Also, 
The distance between crest and trough will be reduced, which implies that there will be decrease in waves wavelength.
This can also be verified using wave equation;
V = Fλ
At constant velocity, 
F ∝ ¹/λ
Thus, decrease in wavelength will cause increase in frequency of the waves. 
The right answer is : The waves will increase in frequency 
 
        
             
        
        
        
Calculate the magnitude of the linear momen- tum for each of the following cases a) a proton with mass 1.67 × 10-27 kg mov- ing with a velocity of 6 × 106 m/s. Answer in units of kg · m/s.