Question

A truck travelling due north at 50 km/hr turns west and travels at the same speed.what is the change in velocity.

Answer 1

see the above solution

Answer 2

Answer:

$\Delta v\ =\ 70.71\ km/hr.$

Explanation:

Given,

• Speed of the truck towards north = $\vec{v_1}\ =\ 50\ km/hr.$
• Speed of the truck towards west = $\vec{v_2}\ =\ 50\ km/hr.$

Now truck is initially in the north direction, after that it changes its speed towards west direction with same speed. Therefore the angel between the two velocities is $90^o.$

Let $\Delta v$ be the change in the velocity of the truck.

From the vector addition,

$\therefore \Delta\ v\ =\ \vec{v_2}\ -\ \vec{v_1}\\\Rightarrow \Delta v\ =\ \sqrt{v_1^2\ +\ v_2^2\ +\ 2v_1v_2cos\theta}\\\Rightarrow \Delta v\ =\ \sqrt{50^o\ +\ 50^2\ +\ 2\times 50\times 50\times cos90^o}\\\Rightarrow \Delta v\ =\ 70.71 m/s.$

Direction of the change in speed is in the north east direction.

Hence the change in the velocity is 70.71 km/hr.