Answer:
a) 0 N
b) 6 N
c) So the applied force must be greater than 16 newton.
Explanation:
Given:
weight of the box,
coefficient of static friction between the box and horizontal surface,
coefficient of kinetic friction,
Here the given value of coefficient of static friction is understated, it is given here as the maximum value of the coefficient of static friction which is variable according to the applied force on the body tending to promote a relative motion between the surfaces.
a)
When no horizontal force is applied on the box and the box is at rest then according to the Newton's first law of motion the box tends to have its initial state of rest and all the forces acting on the box are in equilibrium. Hence no frictional force acts on the box.
b)
When a monkey applies a force of 6 N on the box and it does not move then the contact surface friction also applies the equal amount of force in the opposite direction which balances out the applied force, this will happens upto the maximum coefficient of friction which is stated as coefficient of static friction in the question.
c)
the minimum force required to move the box must be greater than the maximum force of friction which resists the relative motion.
We have the maximum frictional force as:
So the applied force must be greater than 16 newton.
Answer:
1) 65 m
2) 40 m/s downward
Explanation:
Using for both questions the kinematic equation
v² = u² + 2as
and ignoring air resistance.
1) h = 60 + √(20²/(2(9.8))) = 64.51753...
2) v = √(20² + 2(9.8)(60)) = 39.69886...
Answer:
≈ 6.68 m/s
Explanation:
A suitable formula is ...
vf^2 -vi^2 = 2ad
where vi and vf are the initial and final velocities, a is the acceleration, and d is the distance covered.
We note that if the initial launch direction is upward, the velocity of the ball when it comes back to its initial position is the same speed, but in the downward direction. Hence the problem is no different than if the ball were initially launched downward.
Then ...
vf = √(2ad +vi^2) = √(2·9.8 m/s^2·1.0 m+(5 m/s)^2) = √44.6 m/s
vf ≈ 6.68 m/s
The ball hits the ground with a speed of about 6.68 meters per second.
__
We assume the launch direction is either up or down.
Answer:
My arms are doing a negative work
Explanation:
When you set something on the ground, the displacement of the object set towards the ground is in the downward direction. which means that, in this case, there is a downward displacement.
As the object is set on the ground, the force exerted by the arms on the object acts in the upward direction.
Summarily, direction of force is upwards while the direction of displacement is downwards.
Since the force and displacement act in opposite direction, a negative work is said to be done.
Answer:
Explanation:
Given
Force P is acting upward
C is vertical contact Force
W is the weight of the crate
As P is unable to move the Block therefore Normal reaction keeps on acting on block
thus we can say that
P-W+C=0
P=W-C