Here when an object is placed on the level floor then in that case there are two forces on the object
1). Weight of object downwards (mg)
2). Normal force due to floor which will counterbalance the weight (N)
so when no force is applied on the box at that time normal force is counter balanced by weight.
Now here it is given that A person tried to lift the box upwards
So now there are two forces on the box
1). Applied force of person
2). Normal force due to ground
So now these two forces will counter balance the weight of the crate
So we can write an equation for force balance like
given that
here
m = 30 kg and
g = acceleration due to gravity = 10 m/s^2
now from above equation
So force applied by the person must be 150 N
Answer:
Option A
Explanation:
By law if conservation of momentum we know that the the initial and final momentum of a system remains conserved . Therefore the final momentum of system will be 400 kg -m/s
<u>Proof</u><u> </u><u>:</u><u>-</u>
Let the final momentum of car be " x " .
By Law of conservation of momentum ,
→ m1 u1 + m2 u2 = m1 v1 + m2 v2
→ 400 kg m/s + 0 = 500 kg - m/s + x
→ x = 400 - 500 kg m/s
→ x = -100 kg - m/s
Combined momentum = -100 + 500 = 400 kg-m/s
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<em>*</em><em>*</em><em>Edits</em><em> </em><em>are </em><em>appreciated</em><em>*</em><em>*</em>