g A 45.0 - kg girl is standing on a 150. - kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is
2 answers:
Answer:
her velocity relative to the surface of the ice is 1.154 m/s
The positive velocity indicates that her velocity relative to the surface of the ice is in the same direction with her velocity relative to plank.
Explanation:
Given;
mass of the girl, = 45.0 - kg
mass of the plank, = 150 kg
velocity of the girl relative to the plank, = 1.5 m/s
Velocity of the plank relative to the ice, = ?
Velocity of the girl relative to the ice, = ?
Thus, velocity of the girl relative to the ice can be calculated as;
=
+
= 1.5 +
-----------equation (i)
From the principle of conservation of energy;
45 + 150
= 0
3 + 10
= 0 ------------equation (ii)
From equation (i); =
- 1.5
Substitute in in equation (ii)
3 + 10(
- 1.5) = 0
3 + 10
-15 = 0
13 = 15
= 15/13
= 1.154 m/s
The positive velocity indicates that her velocity relative to the surface of the ice is in the same direction with her velocity relative to plank.
You might be interested in
Answer:
Mass and velocity.
Explanation:
Kinetic energy <u>is the energy that an object has due to its movement</u>, mathematically it is represented as follows:
where is the mass of the object, and
is its velocity at a given point in time.
So we can see that to find the kinetic energy just before the ball hits the gound, we need the quantities:
- mass of the ball
- velocity of the ball before it hits the ground
With the knowledge of these two quantities the kinetic energy of the ball before touching the gound can be determined.