Question

A body is thrown at angle 30^o to the horizontal with the velocity of 30 m/s. After 1 sec, its velocity will be (in m/s) (g = 10 m/s²)

• A. $10\sqrt{7}$
• B. $700\sqrt{10}$
• C. $100\sqrt{7}$
• D. $\sqrt{40}$

Answer 1

Answer: (A)

$10\sqrt{7}$

Answer 2

From the formula of instantaneous velocity

$v = \sqrt{u^{2} + g^{2}t^{2} - 2ugt\sin\theta}$

$v = \sqrt{(30)^{2} + (10)^{2} \times 1^{2} - 2 \times 30 \times 10 \times 1 \times \sin 30^{o}}$

$= 10\sqrt{7}m/s$