Three significant figures
Answer: 2.5
Explanation:
The mass of bullet = 20kg
The momentum of the bullet = 10kg m/s
The kinetic energy of this bullet in Kj will be calculated as:
= p² / 2m
= 10² /(2 × 20)
= (10 × 10) /(2 × 20)
= 100/40
= 2.5
Therefore, the correct option is C.
Answer:
(a) 47.08°
(b) 47.50°
Explanation:
Angle of incidence = 78.9°
<u>For blue light :
</u>
Using Snell's law as:
Where,
Θ₁ is the angle of incidence
Θ₂ is the angle of refraction
n₂ is the refractive index for blue light which is 1.340
n₁ is the refractive index of air which is 1
So,
Angle of refraction for blue light = sin⁻¹ 0.7323 = 47.08°.
<u>For red light :
</u>
Using Snell's law as:
Where,
Θ₁ is the angle of incidence
Θ₂ is the angle of refraction
n₂ is the refractive index for red light which is 1.331
n₁ is the refractive index of air which is 1
So,
Angle of refraction for red light = sin⁻¹ 0.7373 = 47.50°.
The weight of the load is (mass) x (gravity).
The work done to lift it is (weight) x (distance) = (mass) x (gravity) x (distance)
The power is (work)/(time) =
(mass) x (gravity) x (distance) / (time) =
(500 kg) x (9.8 m/s²) x (12 m) / (1 sec) =
(500 x 9.8 x 12 / 1) (kg-m / sec²) (m) / (sec) =
(500 x 9.8 x 12 / 1) newton - meter / sec =
(500 x 9.8 x 12 / 1) joule / sec =
58,800 watts
= <em>58.8 kW</em>
= about 78.8 horsepower