Question

If the velocity is v = 2i + t²j - 9k, then the magnitude of acceleration at t = 0.5 s is
(a) 1m s⁻²
(b) 2 m s⁻²
(c) zero
(d) -1 m s⁻²

Answer 1

Hey.

As v = 2i + t²j - 9k

and we know that
$a \: \: = \: \frac{dv}{dt}$

$so \: \: a \: = \frac{d(2i + {t}^{2}j \: - 9k) }{dt} \\ \\ or \: \: a \: = \: 0 + 2tj - 0 \\ \\ so \: \: a \: = 2tj$
so at t = 0.5 s

$so \: \: a \: = \: 2(0.5)j \: \: m {s}^{ - 2} \\ \\ \: \: \: \: a \: = \: 1.0 j \: \: m {s}^{ - 2} \\ \\ so \: |a| \: = \: 1.0 \: \: m {s}^{ - 2}$

So, (a) is correct .

Thanks.

Answer 2

Answer:

A (1m-2) is correct answer

Explanation:

correct option is A