Answer:
Visible, or infrared lights
Answer:
390 J
Explanation:
m = 3 kg
u = 16 i + 2 j
(a) Magnitude of velocity =
= 16.1245 m/s
KEi = 1/2 m v^2 = 0.5 x 3 x 16.1245 = 390 J
(b) v = 18 i + 14 j
Magnitude of velocity =
= 22.804 m/s
KEf = 1/2 m v^2 = 0.5 x 3 x 22.804 = 780 J
According to the work energy theorem
Work done = change in KE = KEf - KEi = 780 - 390 = 390 J
Answer:
The velocity of block = 0.188 
Explanation:
Mass m = 5.6 kg
k = 1040 
= 0.26
0.035 m ,
= 0
0.02 m
From work energy theorem
--------- (1)
Kinetic energy
------- (1)
Potential energy
------- (2)
Work done
W = F.s ------ (3)
From Newton's second law
= mg
= 5.6 × 9.81 = 54.9 N
Friction force = 0.4 × 54.9 = 21.9 N
Now the work done by the friction
= - 21.9 × 0.015
= - 0.329 J
Now kinetic energy
At point 1




0.637 J
At point 2


Potential energy


J
From equation (1) we get
0 + 0.637 - 0.329 = 2.8
+ 0.208
2.8
= 0.1
0.188 
This is the velocity of block.