a) 2.75 s
The vertical position of the ball at time t is given by the equation
where
h = 4 m is the initial height of the ball
u = 12 m/s is the initial velocity of the ball (upward)
g = 9.8 m/s^2 is the acceleration of gravity (downward)
We can find the time t at which the ball reaches the ground by substituting y=0 into the equation:
This is a second-order equation. By solving it for t, we find:
t = -0.30 s
t = 2.75 s
The first solution is negative, so we discard it; the second solution, t = 2.75 s, is the one we are looking for.
b) -15.0 m/s (downward)
The final velocity of the ball can be calculated by using the equation:
where
u = 12 m/s is the initial (upward) velocity
g = 9.8 m/s^2 is the acceleration of gravity (downward)
t is the time
By subsisuting t = 2.75 s, we find the velocity of the ball as it reaches the ground:
And the negative sign means the direction is downward.
Answer:
B. 0.552
Explanation:
To find the resistance in the circuit above, u simply divide the current in the circuit by the voltage to get the resistance.
Answer:
Outer Shell
Explanation:
an electron of an atom, located in the outermost shell (valence shell) of the atom, that can be transferred to or shared with another atom. An electron in one of the outer shells of an atom that can participate in forming chemical bonds with other atoms. read more
Answer:
K = 0.076 J
Explanation:
The height of the target, h = 0.860 m
The mass of the steel ball, m = 0.0120 kg
Distance moved, d = 1.50 m
We need to find the kinetic energy (in joules) of the target ball just after it is struck. Let t is the time taken by the ball to reach the ground.
Put all the values,
The velocity of the ball is :
The kinetic energy of the ball is :
So, the required kinetic energy is 0.076 J.
Answer:
friction force
Explanation:
force of friction is opposite to the force applied it resist the motion
