Answer:
W
Explanation:
= Temperature of the room = 22.0 °C = 22 + 273 = 295 K
= Temperature of the skin = 33.0 °C = 33 + 273 = 306 K
= Surface area = 1.50 m²
= emissivity = 0.97
= Stefan's constant = 5.67 x 10⁻⁸ Wm⁻² K⁻⁴
Rate of heat transfer is given as
W
Answer:
15.24 m/s in the downward direction
Explanation:
Given that the initial upward velocity of the ball is 24 m/s.
Assuming that the upward direction is positive.
As gravitational force acts in the downward direction and the direction of acceleration is the same as the direction of force, so the acceleration due to gravity will be negative.
Now, from the equation of motion, when an object is launched with initial velocity u, the final velocity, v, of an object after time t is v=u+at.
Given that u=24 m/s, t=4 seconds, .
So, the final velocity is
m/s
Here, the negative sign means the final velocity is in the downward direction.
Hence, the velocity after 4 seconds is 15.24 m/s in the downward direction.