(10) if \( \overline{\text { distance of } 3 \mathrm{~km} \text {. from B }} \) (10) If \( \vec{v}_{A B}=20 \hat{c}, \vec{v}_{B}=-15 \hat{c} \), then \( \vec{v}_{A}= \) (a) \( 5 \hat{\mathrm{c}} \) (b) \( -35 \hat{c} \) (c) \( -5 \hat{\mathrm{c}} \) (d) \( 35 \hat{c} \) the captain of the destroyer as it moves with speed \( 18 \mathrm{~km} . / \mathrm{hr} \). a way from him, then the destroyer fired a torpedo with a speed \( 108 \mathrm{~km} . / \mathrm{hr} \). to hit the enemy ship after 3 minutes, then the distance between the destroyer and the ship at the moment of firing the torpedo \( = \) \( \qquad \) km . (a) 5.4 (b) 6.6 (c) 7.2 (d) 4.5
Upstudy AI Solution
Answer
Solution

Sign in to Unlock Answers for Free!
A Learning Platform Trusted by Millions of Real Students and Teachers.

Answered by UpStudy AI and reviewed by a Professional Tutor
The Deep Dive
When adding vector velocities, it's important to consider the direction and magnitude correctly. Here, \( \vec{v}_{A} = \vec{v}_{AB} + \vec{v}_{B} \). So, using the given values, you would calculate \( \vec{v}_{A} = 20\hat{c} + (-15\hat{c}) = 5\hat{c} \). Answer (a) \( 5 \hat{\mathrm{c}} \) is the correct choice. For the torpedo problem, first, find the distance the destroyer moves while firing the torpedo. In 3 minutes (which is 0.05 hours) at 18 km/h, it travels \( 18 \times 0.05 = 0.9 \) km. Then, the torpedo speed in km/min is \( 108/60 = 1.8 \) km/min, so in 3 minutes, the torpedo travels \( 1.8 \times 3 = 5.4 \) km. Therefore, the total distance from the destroyer to the ship at the moment of firing is \( 5.4 \) km, making option (a) the right answer here!