Starting at t = 0s, a horizontal net force F = (0.275N/s)ti+(-0.460N/s2)t^2j is applied to a box that has an initial momentum p = (-2.90kg?m/s)i+(3.95kg?m/s)j. What is the momentum of the box at t = 2.05s? Enter the x and y components of the momentum separated by a comma.

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Answer:

(-2.32, 2.63) kg m/s

Explanation:

From Newton's second law of motion, force is the rate of change of momentum. Mathematically,

[tex]F = \dfrac{dp}{dt}[/tex]

where p is the momentum.

Integrating both sides,

[tex]p = \int\!F\, dt + C[/tex]

where C is a constant of integration determined by initial values.

[tex]p = \int\!(0.275t\,\hat{i} - 0.460t^2\,\hat{j}) dt + C[/tex]

[tex]p = \dfrac{0.275}{2}t^2\,\hat{i} - \dfrac{0.460}{3}t^3\,\hat{j} + C[/tex]

The initial momentum is when t = 0.

[tex]-2.90\,\hat{i}+3.95\,\hat{j} = \dfrac{0.275}{2}0^2\,\hat{i} - \dfrac{0.460}{3}0^3\,\hat{j} + C[/tex]

[tex]C = -2.90\,\hat{i}+3.95\,\hat{j}[/tex]

Hence,

[tex]p = \dfrac{0.275}{2}t^2\,\hat{i} - \dfrac{0.460}{3}t^3\,\hat{j} -2.90\,\hat{i}+3.95\,\hat{j} = (\dfrac{0.275}{2}t^2-2,90)\,\hat{i} + (3.95-\dfrac{0.460}{3}t^3)\,\hat{j}[/tex]

At t = 2.05 s,

[tex]p = (\dfrac{0.275}{2}(2.05)^2-2,90)\,\hat{i} + (3.95-\dfrac{0.460}{3}(2.05)^3)\,\hat{j}[/tex]

[tex]p = -2.32\,\hat{i} + 2.63\,\hat{j}[/tex]

Thus, p = (-2.32, 2.63) kg m/s

The x and y components of the momentum are -2.32 and 0.63 kg m/s respectively for the box at 2.05 s.

According to the second law of motion,  force is the rate of change of momentum.

[tex]\bold {F = \dfrac {dp}{dt}}[/tex]

Where,

p - momentum

Integrate both sides,

[tex]\bold {p = \int\limits F \, dt+C }[/tex]

Where,

C - constant of integration

[tex]\bold {p = \int\limits {0.275t\ \hat {i} - 0.0460t^2 \hat j )} \, dt+C }\\\\\bold {p = (\dfrac {0.275t^2}{2}\ \hat {i} - \dfrac {0.0460}{3}t^2 \hat j ) \, dt+C }[/tex]

For initial momentum t = 0

[tex]\bold { (-2.90)\hat i+(3.95kg)\hat j =\bold (\dfrac {0.275t^2}{2}\ \hat {i} - \dfrac {0.0460}{3}t^2 \hat j ) \, dt+C } }\\\\\bold {C = (-2.90)\hat i+(3.95kg)\hat j }[/tex]

Thus, momentum at t= 2.5 sec,

[tex]\bold {p = (\dfrac {0.275\times (2.05)^2}{2}\ \hat {i} - \dfrac {0.0460}{3}(0.25)^3 \hat j ) \, dt+C }\\\\\bold {p = {- 2.32 \hat {i} - 0.63 \hat j )} }\\\\\bold {p = {- 2.32, 0.63\ kg.m/s )} }\\[/tex]

The x and y components of the momentum are -2.32 and 0.63 kg m/s respectively for the box at 2.05 s.

To know more about momentum,

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