Answer:
X(t) = 9.8 *t - 4.9 * t^2
Explanation:
We set a frame of reference with origin at the hand of the girl the moment she releases the ball. We assume her hand will be in the same position when she catches it again. The positive X axis point upwards.The ball will be subject to a constant gravitational acceleration of -9.81 m/s^2.
We use the equation for position under constant acceleration:
X(t) = X0 + V0 * t + 1/2 * a *t^2
X0 = 0 because it is at the origin of the coordinate system.
We know that at t = 2, the position will be zero.
X(2) = 0 = V0 * 2 + 1/2 * -9.81 * 2^2
0 = 2 * V0 - 4.9 * 4
2 * V0 = 19.6
V0 = 9.8 m/s
Then the position of the ball as a function of time is:
X(t) = 9.8 *t - 4.9 * t^2
Two factors determine whether a substance is a solid, a liquid, or a gas: The kinetic energies of the particles (atoms, molecules, or ions) that make up a substance. Kinetic energy tends to keep the particles moving apart. The attractive intermolecular forces between particles that tend to draw the particles together.
Answer:
B. parents
Explanation:
one of the conclusions from Einsteins relativity theory for his equation E=
(where E is energy, m is mass and C is the speed of light),
is that time moves relative to the observer. Time moves more slowly when the observer is in motion (time dilation), therefore an individual in motion ages more slowly than someone at rest. This in fact happened when astronaut Scot Kelly spent nearly a year on board the international space station and on his return, his twin brother had aged slightly faster than him. In conclusion, if a space trip finds a son or daughter is biologically older than his or her parents, the space trip was taken by the parents.
There is a direct relationship between between an object's weight and its mass.
Weight is actually the force of gravity on the object's mass and it can be calculated by multiplying the object's mass and the acceleration due to gravity. The higher the mass, the higher the weight and the lower the mass, the lower the object's weight. Thus, the relationship is direct.
Answer:
0.661 s, 5.29 m
Explanation:
In the y direction:
Δy = 2.14 m
v₀ = 0 m/s
a = 9.8 m/s²
Find: t
Δy = v₀ t + ½ at²
(2.14 m) = (0 m/s) t + ½ (9.8 m/s²) t²
t = 0.661 s
In the x direction:
v₀ = 8 m/s
a = 0 m/s²
t = 0.661 s
Find: Δx
Δx = v₀ t + ½ at²
Δx = (8 m/s) (0.661 s) + ½ (0 m/s²) (0.661 s)²
Δx = 5.29 m
Round as needed.
