Winston stands on the edge of a building's flat roof, 12 m above the ground, and throws a 147.0-g baseball straight down. the ba
ll hits the ground at a speed of 18 m/s. what was the initial speed of the ball?
1 answer:
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Answer:
<em>Thus, the object is accelerating to the left</em>
Explanation:
<u>The Net Force</u>
The net force is the result of adding all the forces as vectors acting on a body.
Each vector can be expressed in its rectangular components Fx and Fy, and the sum is the sum of the rectangular components separately.
Second Newton's law gives the relation between the net force and the acceleration of the body:
We can see the acceleration is a vector with the same direction as the net force.
The diagram shows two vertical forces and two horizontal forces.
The vertical forces are acting in opposite directions and with the same magnitude, thus they cancel out, leaving zero net force in the y-axis.
The horizontal forces are opposite and with different magnitudes. Since the force acting to the left (F3) has a greater magnitude than the force acting to the right (F4), there is a net force directed to the left with a magnitude of 60 N - 20 N = 40 N
Thus, the object is accelerating to the left
Answer:
electrons
Explanation:
The magnitude of the electric field outside an electrically charged sphere is given by the equation
where
k is the Coulomb's constant
Q is the charge stored on the sphere
r is the distance (from the centre of the sphere) at which the field is calculated
In this problem, the cloud is assumed to be a charged sphere, so we have:
is the maximum electric field strength tolerated by the air before breakdown occurs
is the radius of the sphere
Re-arranging the equation for Q, we find the maximum charge that can be stored on the cloud:
Assuming that the cloud is negatively charged, then
And since the charge of one electron is
The number of excess electrons on the cloud is