Answer:
175.96 g
Explanation:
Potential energy required for the man to climb 7.07 km = m g h.
= 64 x 9.8 x 7070
= 4.434 x 10⁶ J
= 4.434 X 10⁶ / 4.2 cals
= 1.0557 x 10⁶ cals
= 1.0557 x 10⁶ / 6000 g of butter
= 175.96 g of butter.
Answer:
4.42 x 10⁷ W/m²
Explanation:
A = energy absorbed = 500 J
η = efficiency = 0.90
E = Total energy
Total energy is given as
E = A/η
E = 500/0.90
E = 555.55 J
t = time = 4.00 s
Power of the beam is given as
P = E /t
P = 555.55/4.00
P = 138.88 Watt
d = diameter of the circular spot = 2.00 mm = 2 x 10⁻³ m
Area of the circular spot is given as
A = (0.25) πd²
A = (0.25) (3.14) (2 x 10⁻³)²
A = 3.14 x 10⁻⁶ m²
Intensity of the beam is given as
I = P /A
I = 138.88 / (3.14 x 10⁻⁶)
I = 4.42 x 10⁷ W/m²