How many signifficant figures do the following number have 258
1 answer:
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The correct answer to the question is : 29.88 m.
EXPLANATION :
As per the question, the mass of the rock m = 50 Kg.
The rock is rolling off the edges of the cliff.
The final velocity of the rock when it hits the ground v = 24 .2 m/s.
Let the height of the cliff is h.
The potential energy gained by the rock at the top of the cliff = mgh.
Here, g is known as acceleration due to gravity, and g =
When the rock rolls off the edge of the cliff, the potential energy is converted into kinetic energy.
When the rock hits the ground, whole of its potential energy is converted into its kinetic energy.
The kinetic energy of the rock when it touches the ground is given as -
Kinetic energy K.E = .
From above we know that -
Kinetic energy at the bottom of the cliff = potential energy at a height h
⇒
⇒
⇒
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Hence, the height of the cliff is 29.88 m
Answer:
2,87 *
Explanation:
When the bullets meet at the center and collide, since momentum is a vectoral quantity, their momentum vectors even up and are sumof zero. Formula of momentum is P = m.v , where m is mass and v is velocity. Let’s name the first two bullets as x,y and the one which mass is unknown as z. Then calculate momentum of x and y:
Px= 5,30 * * 301 = 1,5953 kg*m/s
Py= 5,30 * * 301 = 1,5953 kg*m/s
The angle between x and y bullets is 120°, and we know that if the angle between two equal magnitude vectors is 120°, the magnitude of the resultant vector will be equal to first two and placed in exact middle of two vectors. So we can say total momentum of x and y (Px+Py) equals to 1,5953 kg*m/s as well (Shown in the figure).
For z bullet to equalize the total momentum of x and y bullets, it needs to have the same amount of momentum in the opposite way.
Pz = 1,5953 = m * 554
m = 2,87 * kg
