d 30 minutes a day , 5 days a week
Answer:
27.1m/s
Explanation:
Given parameters:
Height of the building = 30m
Initial velocity = 12m/s
Unknown:
Final velocity = ?
Solution:
We apply one of the kinematics equation to solve this problem:
v² = u² + 2gh
v is the final velocity
u is the initial velocity
g is the acceleration due to gravity
h is the height
v² = 12² + (2 x 9.8 x 30)
v = 27.1m/s
However here coefficient of friction is not given so unable to calculate.
You can calculate it by below formula.
The formula given by
Or
u is coefficient of friction
N is normal reaction.
Here..
box doesn't move means the force if limiting friction is greater than applied force.
Answer:
gravitational force
Explanation:
We have four types of fundamental forces in nature
1) Electromagnetic force: It is of either repulsive or attractive type of force and this depends on distance between charges and polarity of charge.
2) Strong and weak nuclear force: this is also of attractive or repulsive type of force and it only depends on distance between two nuclei.
3) Gravitational force: It depends on the mass of the objects and it is only attraction type of force.
so here all matter in universe attract each other only due to gravitational force because all other forces are of both type i.e. attraction and repulsion both.
so correct answer will be
gravitational force
