Answer:
v = 10 m/s
Explanation:
given,
Mass of large fish, M = 5 Kg
speed of swimming, v' = 1 m/s
mass of small fish, m = 500 g = 0.5 Kg
speed of the fish = v
using conservation of momentum
m v + M v' = M u' + m u
final speed of both the speed is zero.
- 0.5 x v + 5 x 1 = 0
negative sign is used because small fish is moving in opposite direction.
now,
0.5 v = 5
v = 10 m/s
hence, the speed of the small fish is equal to 10 m/s.
<h2>
The average speed of the moon around the earth is 1021.74 m/s</h2>
Explanation:
Radius of moon around earth, r = 3.84 × 10⁸ m
Circumference of orbit = 2πr = 2 x 3.14 x 3.84 × 10⁸
Circumference of orbit = 2.41 x 10⁹ m
Time taken, t = 27.3 days = 27.3 x 24 x 60 x 60 = 2358720 seconds
We have
Circumference of orbit = Speed of moon x Time taken
2.41 x 10⁹ = Speed of moon x 2358720
Speed of moon = 1021.74 m/s
The average speed of the moon around the earth is 1021.74 m/s
Answer:
Explanation:
Person suffering from myopia is unable to see objects beyond 50 cm because far point of his vision is 50 cm . He requires a concave lens
( diverging lens ) to correct his vision .
After using the lens ,
ray of light coming from far off place will appear to be coming from 50 cm after refraction through lens so it will be focused on retina .
object distance u = ∝
image distance v = - 50 cm
focal length f = ?
1 / v - 1 / u = 1 /f
- 1 / 50 - 1 / ∝ = 1 / f
- 1 / 50 = 1 / f
f = - 50 cm
focal length is negative so len is concave.
He requires concave lens of focal length 50 cm .