Answer:
Potential energy of book = 7.5 J
Explanation:
Given:
Weight of book = 5 N
Height of shelf = 1.5 meter
Find:
Potential energy of book
Computation:
Weight = Mass x Acceleration of gravity
Mass x Acceleration of gravity = 5 N
Potential energy = Mass x Acceleration of gravity x Height
Potential energy of book = Mass x Acceleration of gravity x Height
We know that;
Mass x Acceleration of gravity = 5 N
So,
Potential energy of book = 5 x 1.5 
Potential energy of book = 7.5 J
 
        
             
        
        
        
Answer:
time will elapse before it return to  its staring point is 23.6 ns
Explanation:
given data 
speed u = 2.45 ×  m/s
 m/s
uniform electric field E = 1.18 ×  N/C
 N/C
to find out
How much time will elapse before it returns to its starting point
solution
we find acceleration first by electrostatic force that is 
F = Eq
here 
F = ma by newton law
so 
ma = Eq
here m is mass , a is acceleration and E is uniform electric field and q is charge of electron
so 
put here all value 
9.11 ×  kg ×a = 1.18 ×
 kg ×a = 1.18 ×  × 1.602 ×
 × 1.602 ×  
 
a = 20.75 ×  m/s²
 m/s²
so acceleration is 20.75 ×  m/s²
 m/s²
and
time required by electron before come rest is 
use equation of motion
v = u + at 
here v is zero and u is speed given and t is time so put all value
2.45 ×  = 0 + 20.75 ×
 = 0 + 20.75 ×  (t)
 (t) 
t = 11.80 ×  s
 s
so time will elapse before it return to  its staring point is
time = 2t 
time = 2 ×11.80 ×  
 
time is 23.6 ×  s
 s
time will elapse before it return to  its staring point is 23.6 ns
 
        
             
        
        
        
<span>The support force is 15 N. The net force on the book is zero.</span>
        
             
        
        
        
Answer:
momentum formula = Mass × Velocity