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# Physics Problem?

The position of a particle as a function of time is given by r =( 6.5 i^+ 2.1 j^)t2m, where t is in seconds.

I need to find what is the particle s speed at t1 = 2.9 s ?

Update:

The answer was 40 m/s

### 3 Answers

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- oubaasLv 710 months ago
acceleration a = 2(6.5^2+2.1^2)^0,5

V = a*t = 5.8*6.831 = 39.62 m/sec

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- VamanLv 710 months ago
r =( 6.5 i^+ 2.1 j^)t2m, where t is in seconds.

This gives

x= 6.5 t^2, dx/dt= 13 t. After t=1.9, x velocity=24.7

y=2.1 t^1, dy/dt=4.2, After 1.9, y velocity =7.98

The msgnitude of velocity = swrt(vx^2+vy^2)=sqrt(24.7^2+7.98^2)=25.95 m/s

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- alexLv 710 months ago
Rules

v = dr/dt

speed = |v|

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- oubaasLv 710 months agoReport
no matter calculus ...pls have a look to my solution

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