Answer electrons are negative. Protons are positive, and neutrons are neutral
 
        
             
        
        
        
Answer:
option D
Explanation:
given.
horizontal velocity of arrow and a ball given as  50 m/s and 44 m/s respectively from the top of a building over flat ground.
In vertical direction, they are both identical
In vertical direction the initial velocity of arrow and a ball  is 0  m/s
Their acceleration due to gravity  is same for both arrow and a ball  9.8 m/s²
they will react bottom at the same time
  time of flight is same for both
now,
In horizontal direction,
distance = speed × time
Since speed is more for arrow, it will travel more horizontal distance  at the same time.
the correct answer is option D
 
        
             
        
        
        
Answer:
Explanation:
Let initial extension in the spring= x₀
Force on the spring = F₀ 
Let spring constant = k 
Fo = k x₀
Fn = 3k x₀
Fn /Fo = 3
PEs0 ( ORIGINAL)  =1/2 k x₀²
PEsn ( NEW)  =1/2 k (3x₀)²
PEsn / PEs0 = 9 
 
        
             
        
        
        
Answer:
Explanation:
Work done in lifting the weight once = mgh 
= 20 x 9.8 x (1.9+1.7) 
= 705.6 J  
= 705.6 / 4.2 calorie 
= 168 cals 
Total energy to be spent = 600 x 10³ cals 
No of times weight is required to be lifted 
= 600 x 10³ / 168 
= 3.57  x 10³ times 
Total time to be taken = 2 x 3.57 x 10³
= 7.14 x 10³ s 
=119 minutes . 
 
        
             
        
        
        
<span>According to its definition, friction is generated when atoms interfere with each other on sliding surfaces.</span>