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sparklegemini

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HW Template missing as it was moved from another forum

1. problem

Two forces, F1 and F2(t), act on a mass m = 1.0 kg. Force 1 F1 is to the left in the negative x-direction and force F2(t) is to the right in the positive x-direction. F1 is constant with a magnitude of 1.0 N whereas F2(t) has a magnitude of 2.0 N for the time interval 0.0 s ≤ t ≤ 5.0 s and drops to zero after 5.0 s. The mass is at rest at time t = 0.0 s.

a) Sketch the acceleration versus time graph for the time interval 0.0 s ≤ t ≤ 15.0 s for the mass m.

b) sketch the v(t) for the same time as question a.

2. attemps:

I am confusing about the time t=0s, when the object is at rest, that means a=0 and v=0? no unbalanced forces?

Since f2=2N and f1 =1N during the interval time [0,5]. netforce would be 1N. Because F2(t)=2N during [0,5] and it comes to 0 after 5s. for example t=6s.7.,,,. I believe that i shoud calculate the friction force cos It will be 1N in magnitude and the same negative direction as F1.

Now when t>5s, t=6s, Fnet is now missing F2. Will the mass start acceleration? although I have considered the FFric.? If it does, a=-1m/s/s. so velocity will be -1 at t=6, hence -2,-3... at t=7,8... while a is now constant and has the value of -1?

and if there is friction consideration, fnet =0 cos friction force will resist the tend to accelerate by F1

3. thank in advance

Two forces, F1 and F2(t), act on a mass m = 1.0 kg. Force 1 F1 is to the left in the negative x-direction and force F2(t) is to the right in the positive x-direction. F1 is constant with a magnitude of 1.0 N whereas F2(t) has a magnitude of 2.0 N for the time interval 0.0 s ≤ t ≤ 5.0 s and drops to zero after 5.0 s. The mass is at rest at time t = 0.0 s.

a) Sketch the acceleration versus time graph for the time interval 0.0 s ≤ t ≤ 15.0 s for the mass m.

b) sketch the v(t) for the same time as question a.

2. attemps:

I am confusing about the time t=0s, when the object is at rest, that means a=0 and v=0? no unbalanced forces?

Since f2=2N and f1 =1N during the interval time [0,5]. netforce would be 1N. Because F2(t)=2N during [0,5] and it comes to 0 after 5s. for example t=6s.7.,,,. I believe that i shoud calculate the friction force cos It will be 1N in magnitude and the same negative direction as F1.

Now when t>5s, t=6s, Fnet is now missing F2. Will the mass start acceleration? although I have considered the FFric.? If it does, a=-1m/s/s. so velocity will be -1 at t=6, hence -2,-3... at t=7,8... while a is now constant and has the value of -1?

and if there is friction consideration, fnet =0 cos friction force will resist the tend to accelerate by F1

3. thank in advance