Answer:
Explanation:
The boy throw the pencil upward at a speed of 6.33 m/s
Then,
Initial velocity of throw is 6.33 m/s
u = 6.33 m/s.
Time to reach a maximum height of 1.25m
h = 1.25m
Note: at maximum height, the final velocity is zero
v = 0m/s
Acceleration due to gravity is
g = 9.81m/s²
We want to calculate time to reach maximum height
t = ?
Then, applying equation of motion
v = u + gt
But since it is against gravity, then, g is negaive
Then,
v = u - gt
0 = 6.33 - 9.81t
-6.33 = -9.81t
Then,
t = -6.33 / -9.81
t = 0.645 seconds
As a substance is changing from a liquid to a gas, the distance between its molecules increases, and the temperature of the system remains the same.
Option A
<u>Explanation:</u>
The external energy required to change from one state to another is mostly considered as temperature. So on increase in temperature, the solid changes to liquid and the liquid changes to gases. But the temperature remains constant in the system after changing the phase.
This is because when the temperature is increased on a liquid system, the rise in temperature is utilized for breaking the bonds and thus the molecules will be distanced from each other. If we consider liquid - gas phase transition, the gas molecules are farther distanced compared to liquid molecules.
So the rise in temperature is utilized for breaking the bonds and also to provide the kinetic energy to the gas molecules as they are tend to move more freely compared to liquid. Thus, the distance between the molecules increases, and the temperature of the system remains the same on changing from liquid to gas.
Answer:
187.38 m
Explanation:
Using the equation of motion
s = ut + 1/2gt²...................... Equation 1
Where s = distance of fall, u = initial velocity of the rock, t = time taken for the rock to fall from rest, g = acceleration due to gravity of venus.
Given: u = 0 m/s ( from rest), t = 6.5 s, g = 8.87 m/s².
substituting into equation 1
s = 0(6.5) + 1/2(8.87)(6.5)²
s = 0 + 374.7575/2
s = 187.38 m.
Hence the rock will fall 187.38 m
