A 17 N horizontal force F pushes a block weighing 3.0 N against a vertical wall. The coefficient of static friction between the wall and the block is 0.65, and the coefficient of kinetic friction is 0.45. Assume that the block is not moving initially.
(a) Will the block move?
yes
no
(b) In unit-vector notation, what is the force exerted on the block by the wall?
( N) + ( N)
This is a rather straightforward question. I will be happy to critique your thinking.
I got no for a, then im not really sure what to do or where to start for b
okay,
for the xcomponent,
Fx=Fcos(theta), theta = 0 because it is horizontal to the wall, so Fx=17
For the y component
Fy=Fsin(theta), theta=0
Fy=O
vector notation: 17i =0j
yes, it will, in fact, MOVE with the force of Poseidon
To determine whether the block will move, we need to compare the maximum static friction force (Fs_max) with the applied horizontal force (F).
The maximum static friction force can be calculated using the equation:
Fs_max = μs * N
where μs is the coefficient of static friction and N is the normal force exerted on the block by the wall.
The normal force is equal to the weight of the block, which can be calculated as:
N = mg
where m is the mass of the block and g is the acceleration due to gravity (9.8 m/s^2).
Given that the block weighs 3.0 N, we can calculate the normal force:
N = 3.0 N
Now, we can calculate the maximum static friction force:
Fs_max = 0.65 * 3.0 N
Fs_max = 1.95 N
Comparing the maximum static friction force with the applied horizontal force (F = 17 N) tells us whether the block will move.
If F is greater than Fs_max, the block will move.
If F is less than or equal to Fs_max, the block will not move.
In this case, F (17 N) is greater than Fs_max (1.95 N), so the block will move.
Therefore, the answer to part (a) is:
(a) Will the block move?
yes
Now, let's move on to part (b).
The force exerted on the block by the wall can be determined using the equation:
F_wall = -Fs_max
Since the block is moving, we need to use the coefficient of kinetic friction (μk) to calculate the force exerted by the wall.
F_wall = -μk * N
Given that the coefficient of kinetic friction is 0.45, we can calculate the force exerted by the wall:
F_wall = -0.45 * 3.0 N
F_wall = -1.35 N
In unit-vector notation, the force exerted on the block by the wall can be represented as:
F_wall = (-1.35 N) + (0 N)
Therefore, the answer to part (b) is:
(b) In unit-vector notation, what is the force exerted on the block by the wall?
(-1.35 N) + (0 N)