An object has a position given by the radius vector r = [2.0 m + (3.00 m/s)t](i)+ [3.0 m - (2.00 m/s^2)t^2](j). Here (i) and (j) are the unit vectors along x and y and all quantities are in SI units. What is the speed and magnitude of the acceleration in m/s^2 of the object at time t = 2.00 s

Respuesta :

Answer:

The speed of the object is ([tex]3i - 4.00tj[/tex])m/s

The magnitude of the acceleration is 4.00m/s²

Explanation:

Given - position vector;

r = (2.0 + 3.00t)i + (3.0 - 2.00t²)j       -------------------(i)

To get the speed vector ([tex]v[/tex]), take the first derivative of equation (i) with respect to time t as follows;

[tex]v[/tex] = [tex]\frac{dr}{dt}[/tex]

 [tex]v[/tex] = [tex]\frac{d[(2.0 + 3.00t)i + (3.0 - 2.00t^2)j] }{dt}[/tex]  

[tex]v[/tex]  = [tex]3i - 4.00tj[/tex]      ------------------------(ii)

To get the acceleration vector ([tex]a[/tex]), take the first derivative of the speed vector in equation(ii) as follows;

[tex]a = \frac{dv}{dt}[/tex]

[tex]a = \frac{d(3i - 4.00tj)}{dt}[/tex]

[tex]a = -4.00[/tex]j

The magnitude of the acceleration |a| is therefore given by

|a| = |-4.00|

|a| = 4.00 m/s²

In conclusion;

the speed of the object is ([tex]3i - 4.00tj[/tex])m/s

the magnitude of the acceleration is 4.00m/s²