Question

plzz solve this.urgent....​

Answer 1

Solution:

Given:

=> h = 100 m

=> u = 10 m/s

=> Ф = 45°

To Find:

=> Time (in sec)

Formula used:

=> v = u sec Ф

=> v = u + at

So, we know that

=> u = v cos Ф

Where, v = velocity of projectile

=> v = u sec Ф

=> v = 10 × √2

=> v = 10√2 m/s

Now, we know that

=> $\sf{u_{y}}$ = initial velocity along y axis = 0

$\sf{\implies v_{y}=v\;\sin\theta}$

$\sf{\implies v_{y}=10\sqrt{2}\times \dfrac{1}{\sqrt{2}}}$

$\sf{\implies v_{y}=10\;m/s}$

Now, using 1st Equation of motion we will calculate time.

=> v = u + at

=> 10 = 0 + 9.8 m/s² (t)

=> t = (10m/s)/(9.8 m/s²)

=> t = 1.02 s.

Therefore at 1.02 seconds angle of projectile will be equal to 45°.

Answer 2

Answer:

Explanation:

Given:

=> h = 100 m

=> u = 10 m/s

=> Ф = 45°

To Find:

=> Time (in sec)

Formula used:

=> v = u sec Ф

=> v = u + at

So, we know that

=> u = v cos Ф

Where, v = velocity of projectile

=> v = u sec Ф

=> v = 10 × √2

=> v = 10√2 m/s

Now, we know that

=> = initial velocity along y axis = 0

Now, using 1st Equation of motion we will calculate time.

=> v = u + at

=> 10 = 0 + 9.8 m/s² (t)

=> t = (10m/s)/(9.8 m/s²)

=> t = 1.02 s.

Therefore at 1.02 seconds angle of projectile will be equal to 45°.