Answer:
23.52 m/s
Explanation:
The following data were obtained from the question:
Time taken (t) to reach the maximum height = 2.4 s
Acceleration due to gravity (g) = 9.8 m/s²
Initial velocity (u) =..?
At the maximum height, the final velocity (v) is zero. Thus, we can obtain how fast the rock (i.e initial velocity)
was thrown as follow:
v = u – gt (since the rock is going against gravity)
0 = u – (9.8 × 2.4)
0 = u – 23.52
Collect like terms
0 + 23.52 = u
u = 23.52 m/s
Therefore, the rock was thrown at a velocity of 23.52 m/s.
Despite current has a magnitude and a direction, like vectors, it is a scalar because it doesn't obey laws of vector addition. For instance, if we consider a junction of

in a circuit, and two currents entering this junction, we know that the resultant current is just the algebraic sum of the two currents, not the vector sum, so it is not a vector quantity.
Answer:
A stronger force changes increases velocity more due to increased acceleration on the object if the mass is constant as compared to a weaker force.
Explanation:
Force affects how objects behave in terms of motion, direction, shape etc. When an object is in a state of rest, then force is applied, the object starts to move is a particular direction. Increase in the force applied will make the object to speed up which is to say the velocity will increase.
<u>For example:</u>
When a ball is kicked with a player with a force of 10 N the velocity of the ball is recorded to be 3 m/s. When the player is replaced with a kid the force on the ball is 2 N and its velocity is recorded to be 0.3 m/s.
<u>Reasoning</u>
Increased in force applied on an object increases its acceleration resulting to a higher velocity of the object.
F= m * a --------if mass is constant , increased force will increase acceleration and speed up the object.
Answer:
44.4cm
Explanation:
glass has an index of refraction .n = 1.54
radii of curvature of 40 cm R1 = 40 by
radii of curvature of 600 cm R2 = 60
Now, by lens maker formula
1/f = (n - 1) (1/R1 - 1/R2)
Putting in the given values for n = 1.54 , we get f = 22.2


f = 1 / 0.0225
f = 44.4cm
so, focal length in air will be = 44.4 cm