OPTIONS :
A.) the force that the ball exerts on the wall
B.) the frictional force between the wall and the ball
C.) the acceleration of the ball as it approaches the wall
D.) the normal force that the wall exerts on the ball
Answer: D.) the normal force that the wall exerts on the ball
Explanation: The normal force acting on an object can be explained as a force experienced by an object when it comes in contact with a flat surface. The normal force acts perpendicular to the surface of contact.
In the scenario described above, Erica's tennis ball experiences an opposite reaction after hitting the wall.This is in relation to Newton's 3rd law of motion, which states that, For every action, there is an equal and opposite reaction.
The reaction force in this case is the normal force exerted on the ball by the wall perpendicular to the surface of contact.
Answer:Conversion of electric energy to Heat energy
Explanation:Energy is a quantitative energy measured in JOULES or KILOJOULES which must be transferred to a material for a job to be done. It has also been described as the capacity to do work.
In electric toasters the ELECTRIC ENERGY FROM THE SOURCE IS TRANSFERRED INTO THE TOASTER TO BE CONVERTED TO HEAT ENERGY NEEDED TO TOAST FOODS. Other electrical appliances which converts electric energy to Heat energy includes ELECTRIC BOILERS, ELECTRIC COOKERS etc.
Answer:
x=2d
Explanation:
initial stretch in the spring is d
so using Hook's law
at equilibrium position
k×d=mg
where k= spring constant
m= mass of fish
g= acceleration due to gravity.
d=mg/k ................ (1)
in second case by energy conservation
1/2 kx^2=mgx
x=2mg/k
using equation 1
x=2d
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:
136 meters.
Explanation: If it can go 17 meters a second, then after 8 seconds, it will go 136 meters. Multiple 17 by 8 to get your answer.
