Answer:
a)W= 1 J
b)W= 1 J
c)W= 0 J
Explanation:
Given that
m = 5 kg
Coefficient of kinetic friction,K=0.5
d= 10 cm
We know that if velocity is constant it means that the acceleration of the system is zero.Or we can say that all forces are balance in the system.
We know that work is the dot product of force and displacement
W= F.d
The friction force on the box
Fr= K m g
Fr= 0.5 x 5 x 10 = 25 N ( take g =10 m/s²)
Fr=25 N
a)
Acceleration a= 0
So horizontal force F = Fr
W = Fr.d
W=10 x 0.1 J
W= 1 J
b)
The work done by friction force
W= 1 J
c)
The net force on the system is zero because acceleration is zero.
F= 0
So
W= 0 J
Answer:
option b. <em>uniform</em><em> </em><em>population</em>
Answer:
kinetic energy of the train = 2,910.6 x 10⁷ joule
Explanation:
Given:
Mass of train = 3.3 x 10⁷ kg
Speed of train = 42 m/s
Find:
kinetic energy of the train
Computation:
kinetic energy = (1/2)(m)(v²)
kinetic energy of the train = (1/2)(3.3 x 10⁷)(42²)
kinetic energy of the train = (1/2)(3.3 x 10⁷)(1,764)
kinetic energy of the train = (3.3 x 10⁷)(882)
kinetic energy of the train = 2,910.6 x 10⁷ joule
Distance covered by the squirrel to look for an acorn :
d = ( 3 m/s ) × 10 s = 30 m.
Time taken to eat an Acron is 5 seconds.
Time taken to cover distance of 30 m with 2 m/s speed is :

Therefore, total time take to get back to where he started is ( 10+5+15 ) = 30 s.
Hence, this is the required solution.