)m∕s ∴ Acceleration of object is given as a=‌
dv
dt
=‌
d
dt
(8t
â‹€
i
+3t2
â‹€
j
) a=8
â‹€
i
+6t
â‹€
j
ms−2 Hence,according to Newton's second law of motion, force on the object, F=ma=2(8
â‹€
i
+6t
â‹€
j
) ⇒F=16
â‹€
i
+12t
â‹€
j
|F|=√162+(12t)2 ⇒20=√162+(12f)2‌‌[‌ Given, ‌|F|=20N] ⇒‌‌400=256+144t2 ⇒‌‌144t2=144⇒t2=1⇒t=1s Put t=1 s in Eq. (i),we get F=16
â‹€
i
+12
â‹€
j
∴ Angle made by force Frelativeto positive direction of X -axis is given asθ=tan−1(‌