Joanne C. answered 05/22/23
Electrical Engineer / Homeschool Teacher & Tutor 19+ Years
Given:
𝐹 = 40.8 N at an angle of 𝜃=51.2
Mass m = 2.10kg
µk= 0.360
Find: Calculate the magnitude of the acceleration 𝑎 of the mop head
The mop head is moving horizontally. It is not moving vertically. There is no vertical acceleration.
To calculate the acceleration of the mop head. You need to find the sum of the forces in the horizontal direction.
Let Fp = the push force
Let Fk = the force due to kinetic friction.
Let the positive direction be to the right.
When the mop is pushed to the right, the kinetic friction force is opposing it and pushing to the left.
The mop is being pushed at an angle. When we determine the sum of the forces in the horizontal direction, we only use the Fpx = 40.8 cos (51.2)
The formula for Fk= µkFn
FN is the normal force. In this case, since the mop is being pushed at an angle, it will be the force in the y direction due to gravity plus the y component of the force pushing on the mop
FN= mg + 40.8sin(51.2)N
FN= (2.10kg)(9.81m/s2) + (40.8N)sin(51.2)
Fk= µkFN= (0.360)[(2.10kg)(9.81m/s2) + (40.8N)sin(51.2)]
F=ma
The sum of the forces in the horizontal direction would be
Fpx - Fk = max
40.8N cos (51.2) - (0.360)[(2.10kg)(9.81m/s2) + (40.8N)sin(51.2)] = (2.10kg)(ax)
Now you can solve for ax
ax=3.19