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
Answer : The correct option is, (D) Velocity includes rate of change and direction.
Explanation :
Speed : Speed is defined as the distance traveled by an object with respect to the time taken. It is a scalar quantity that means it tell us about the magnitude of an object not direction.
Velocity : Velocity is defined as the rate of change of position of an object with respect to the time. It is a vector quantity that means it tell us about the magnitude and direction of an object.
The only difference between the speed and the velocity is that the velocity tell us about magnitude and direction but speed tell us about magnitude only.
Hence, the correct option is, (D) Velocity includes rate of change and direction.
Answer:
The engine would be warm to touch, and the exhaust gases would be at ambient temperature. The engine would not vibrate nor make any noise. None of the fuel entering the engine would go unused.
Explanation:
In this ideal engine, none of these events would happen due to the nature of the efficiency.
We can define efficiency as the ratio between the used energy and the potential generable energy in the fuel.
n=W, total/(E, available).
However, in real engines the energy generated in the combustion of the fuel transforms into heat (which heates the exhost gases, and the engine therefore transfering some of this heat to the environment). Also, there are some mechanical energy loss due to vibrations and sound, which are also energy that comes from the fuel combustion.
Answer:
A
Explanation:
Straight line with a negative slope
On a velocity_time graph
Answer:
The Gravitational Force is reduced 4 times
Explanation:
The equation of Gravitational force follows:
F = (G*m1*m2)/r^2
Assume that G*m1*m2 = 1 and r = 1:
F = 1/1^2 = 1 N
Multiply the radius by 2
F = 1/2^2 = 1/4 N
So doubling the distance reduces the force 4 times.
