Answer:
0.36s, 2.3s
Explanation:
Let gravitational acceleration g = 9.81 m/s2. And let the throwing point as the ground 0 for the upward motion. The equation of motion for the rock leaving your hand can be written as the following:

where s = 4 m is the position at 4m above your hand.
is the initial speed of the rock when it leaves your hand. g = -9.81m/s2 is the deceleration because it's in the downward direction. And t it the time(s) it take to get to 4m, which we are looking for


t = 2.3 or t = 0.36
Answer: something must drop it over
Explanation:
Answer:
A. Drag
Explanation:
This is because, since friction tends to oppose the motion of an object, and drag affects an object moving in a fluid, the more the friction, the more the drag on the object.
Answer:
1.) Total distance = 70 m
2.) Total displacement = +30m
Explanation:
Distance is a scaler quantity. That is, we will be concerned about its magnitude only and not direction.
Total distance = 10 + 20 + 40 = 70 m
While displacement is a vector quantity. We will consider both the magnitude and its direction.
Forward direction will be positive while backward direction will be negative
Total displacement = +10 - 20 + 40
Total displacement = +30 m
Answer:

Explanation:
k = spring constant of the spring = 40 Nm⁻¹
A = amplitude of the simple harmonic motion = 4 cm = 0.04 m
m = mass of the block attached to spring = 0.20 kg
w = angular frequency of the simple harmonic motion
Angular frequency of the simple harmonic motion is given as 
= Speed of the block as it pass the equilibrium point
Speed of the block as it pass the equilibrium point is given as
