Question

QUESTION 3 The function s = f(t) gives the position of a body moving on a coordinate line, with sin meters and t in seconds. Sa-t3+2t 2.2t, Osts 2 Find the body's speed and acceleration at the end of the time interval. 6 m/sec, -8 m/sec2 -6 m/sec, -8 m/sec 6 m/sec, -2 m/sec2 2 m/sec, 0 m/sec2

Answer 1

s=-+*+2+-21

Velocity is given by

Velocity =

는 [-t + 2t2 - 21

11 - [3] + + =

d = -32 + 2 x

= -3+ + 2 x 2t - 2 x1

= -3° +t-2

Speed = velocity

=|-t'+t-2

0<t< 2

Speed at the end of interval means at $t=2$

Speed = 1-3 x 22 +4 x 2-2 = 6

That is

Speed = 6 m/sec

Acceleration is given by

Acceleration = 1 [velocity

「-3+2 +/-2

d 32 + at

=-3x 中P E 小平

= -3 x 2t +4x1

= -6t+4

At $t=2$

Acceleration = -6 x 2 +4 = -8

That is

Acceleration = -8 m/sec?

Correct option is

6 m/sec, -8 m/sec2

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