Answer:
Explanation:
For this case we have the initial height given:
above the water
We know that the total time from the initial point and the end point it's
So we can use this kinematic formula in order to find the time to travel from the original height to the surface of the water:
We assume that the initial velocity is 0, the final height since it's at the surface so it would be 0m, the acceleration for this case would be the gravity and negative since it's acting downward, replacing we have this:
And solving for t1 we got:
Now we can find the velocity at the surface of the water like this:
Since we know that the total time from the begin and the end it's 5 s and from the calculation before we know that the time to reach the surface of the water is 1.01 s, then the time between the surface of the water and the final depth of the water is 5-1.01= 3.99 s
And then we can find the depth of the lake (D) using the formula for constant velocity like this:
Try B if it is not it I am sorry I checked on Google
The answer would be:
Newton's first law of motion, also known as the Law of Inertia
Here's more about it:
Isaac Newton came up with three laws of motion:
Law of Inertia
Law of Acceleration
Law of Reaction
The law the question is pertaining to is the law of inertia which states:
"An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force."
The main thing you should remember is the phrase "unless acted upon by an unbalanced force."
Let's say you have a book on the counter. It is at rest, if it is not moving. Now how will you move that? You are going to move it by applying force on the book in the direction you want to move it. Unless you apply force enough to move it, it will stay in its position.
Let's say you have a truck. Unless you can apply enough force to move it, it will stay at rest.
Now if you have a moving object, that object will stay in motion and in the same direction unless an unbalanced force will be applied to it. So why does a rolling ball eventually stop? Well the friction and gravity both apply forces on the ball, so it comes out as an unbalanced force.
If the ball were moving in space where both gravity and friction have nothing on it, then it will move continuously until something will stop it.
(This is why astronauts are extra careful when they traverse space and make sure that they're attached carefully on the ship because they can drift off without stopping if they're not secured.)
Answer:
B
Explanation:
Energy at the top of the hill = energy at the bottom of the hill + energy lost
PE = KE + E
mgh = 1/2 mv² + E
(52 kg) (9.8 m/s²) (50.0 m) = 1/2 (52 kg) (25 m/s)² + E
25480 J = 16250 J + E
E = 9230 J