Answer:
Force of the ball against the bat
Explanation:
Newton's third law of motion states that for every action, there is an equal and opposite reaction. When a player hits a ball with a bat, the force the player exerted on the ball through the bat gave the ball a push force in the forward direction. This is an action force. Now that an action has been initiated, there must be a reaction according to Newton's third law of motion. The magnitude of the force on the ball equals the magnitude of the force on the bat. The direction of the force on the ball is opposite to the direction of the force on the ball. The ball will give the bat an equal and opposite force trying to push the bat backward by resisting the impact of the bat. This is the reaction. The ball will only move if the applied force is able to overcome the resisting force by the bat.
Where;
is the action force of the bat against the ball.
is the equal and opposite reaction force of the ball towards the ball.
Answer: His average speed in mph over the last 400 m is 7.7 m/s.
Explanation:
Given: Hicham El Guerrouj of Morocco holds the world record in the 1500 m running race. He ran the final 400 m in a time of 51.9 s.
We know that , speed =
Here , distance = 400m and time = 51.9 s
Then, speed =
Hence, his average speed in mph over the last 400 m is 7.7 m/s.
Answer:
The correct answer is D /
= 1.5
Explanation:
In this exercise the moment of inertia equation should be used
I = ∫ r² dm
In addition to the parallel axis theorem
I = + M D²
Where is the moment of the center of mass, M is the total mass of the body and D the distance from this point to the axis of interest
Let's apply these relationships to our problem, the center of mass of a uniform rod coincides with its geometric center, in this case the rod is 1 m long, so the center of mass is in
L = 100.00 cm (1m / 100 cm) = 1.0000 m
= 50 cm = 0.50 m
Let's calculate the moment of inertia for this point, suppose the rod is on the x-axis and use the concept of linear density
λ = M / L = dm / dx
dm = λ dx
Let's replace in the moment of inertia equation
I = ∫ x² ( λ dx)
We integrate
I = λ x³ / 3
We evaluate between the lower limits x = -L/2 to the upper limit x = L/2
I = λ/3 [(L/2)³ - (-L/2)³] = lam/3 [L³/8 - (-L³ / 8)]
I = λ/3 L³/4
I = 1/12 λ L³
Let's replace the linear density with its value
I = 1/12 (M/L) L³
I = 1/12 M L²
Let's calculate with the given values
I = 1/12 M 1²
I = 1/12 M
This point is the center of mass of the rod
Icm = I = 1/12 M = 8.333 10-2 M
Now let's use the parallel axis theorem to calculate the moment of resection of the new axis, which is 0.30 m from one end, in this case the distance is
D = - x
D = 0.50 - 0.30
D = 0.20 m
Let's calculate
=
+ M D²
= 1/12 M + M 0.202
= M (1/12 + 0.04)
= M 0.123
To find the relationship between the two moments of inertia, divide the quantities
/
= M 0.123 / (M 8.3 10-2)
/
= 1.48
The correct answer is d 1.5
Answer:
The system is still balanced
Explanation:
If we suppose that the boy weights M and the girl m, and are balanced at distances L1 and L2 from the pivot point respectively, thy will be balanced if the resultant torque of all the farces from the pivot pint is cero:
(1)
now they moved to distances (L1)/2 and (L2)/2, the resultant torque will be:
(2)
1/2 can be taken out as a common factor:
(3)
As the the inside of the parenthesis equals equation (1) that equals zero, hte whole equiation equals zero:
(3)
So the system is still balanced