A projectile is projected at 30^ ^ from horizontal with initial velocity 40 ms^ -1 . The velocity of the projectile at t=2 s from the start will be: (Given g=10 m / s^2 )

Correct answer: A. 20 3 ms^ -1 Given, Initial velocity of projectile, u=40 m / s Angle, θ=30^ ^ Time of flight T= 2 u θ g =(2 × 40 × 1)/(10 × 2)=45 ( g=10 m / s^2) It means projectile is at maximum height at t=2 s.At maximum height vertical component of velocity is zero. aligned Velocity at t=2 s=V_ x =u θ=40 30^ ^ & =20 3 ms^ -1 . & aligned

BITSAT 2023Paper 2

Exam: BITSAT
Year: 2023
Paper: Paper 2
Subject: Physics
Chapter: Motion in Two Dimensions

BITSAT 2023 · Paper 2 · Physics · Motion in Two Dimensions

A projectile is projected at 30^ ^ from horizontal with initial...

A projectile is projected at

30^{{}^{\circ}}

from horizontal with initial velocity

40 \mathrm{ ms}^{-1}

. The velocity of the projectile at

\mathrm{t}=2 \mathrm{ s}

from the start will be: (Given

\mathrm{g}=10 \mathrm{ m} / \mathrm{s}^2

)

Options

A $20 \sqrt{3} \mathrm{ ms}^{-1}$
B $40 \sqrt{3} \mathrm{ ms}^{-1}$
C $20 \mathrm{ ms}^{-1}$
D
Zero

Correct answer

A. $20 \sqrt{3} \mathrm{ ms}^{-1}$

Step-by-step solution

Given,
Initial velocity of projectile,

u=40 \mathrm{ m} / \mathrm{s}

Angle,

\theta=30^{{}^{\circ}}

Time of flight

\mathrm{T}=\frac{2 \mathrm{u} \sin \theta}{\mathrm{g}}=\frac{2 \times 40 \times 1}{10 \times 2}=45 \left(\because \mathrm{g}=10 \mathrm{ m}

\mathrm{s}^2\right)<br />It means projectile is at maximum height at

t=2

\mathrm{ s}.At maximum height vertical component

velocity is zero.<br />

\begin{aligned}\\ \text{ Velocity at } \mathrm{t}=2 \mathrm{ s}=\mathrm{V}_{\mathrm{x}}=\mathrm{u} \cos \theta=40 \cos 30^{{}^{\circ}} \\ \\ & =20 \sqrt{3} \mathrm{ ms}^{-1} \text{. }\\ \\ & \\ \end{aligned}

Practice Motion in Two Dimensions on Quantrex Academy →

More from Motion in Two Dimensions

A projectile is projected with velocity of 40 m / s at an angle θ with the horizontal. If… BITSAT 2024 A rigid body rotates about a fixed axis with variable angular velocity equal to α-β t… BITSAT 2024 The range of the projectile projected at an angle of 15^ ^ ∘ with horizontal is 50 m. If… BITSAT 2024 A particle of mass m is projected with a velocity ' u ' making an angle of 30^ ^ ∘ with… BITSAT 2024 A body is thrown with a velocity of 9.8 ms making an angle of 30^ ^ ∘ with the… BITSAT 2024 A projectile is projected with the velocity of (3 i +4 j ) m / s . The horizontal range… BITSAT 2022 A gun fires two bullets at 60^ ^ ∘ and 30^ ^ ∘ with horizontal. The bullets strike at… BITSAT 2021 A projectile A is thrown at an angle of 30^ ^ ∘ to the horizontal from point P. At the… BITSAT 2020 Full Motion in Two Dimensions list All BITSAT PYQs