By Newton's second law,
<em>n</em> + (-<em>w</em>) = 0
<em>p</em> + (-<em>f</em> ) = (20 kg) (2 m/s²)
where <em>n</em> is the magnitude of the normal force, <em>w</em> is the weight of the box, <em>p</em> is the magnitude of the applied force (<em>p</em> for <u>p</u>ush or <u>p</u>ull), and <em>f</em> is the magnitude of the friction force.
Calculate the weight of the box:
<em>w</em> = (20 kg) (9.80 m/s²) = 196 N
Then
<em>n</em> = <em>w</em> = 196 N
and
<em>f</em> = <em>µ</em> <em>n</em> = 0.5 (196 N) = 98 N
Now solve for <em>p</em> :
<em>p</em> - 98 N = 40 N
<em>p</em> = 138 N
The quantity that describes the rate of change of velocity in a given time interval is called acceleration.
Think it would be c, 5.1 g
Answer:
Explanation:
In a rotating system , when a torque is applied , angular acceleration or deceleration takes place . The child is walking towards the center . He must be applying force on the ground . In return , ground must be applying reaction force on him which helps him to go towards the center . These two force of action and reaction are internal forces . One will increase the angular momentum of one and the other force will decrease the angular
momentum of other . But total angular momentum of the whole system will remain constant . So angular momentum will be conserved.