The original Clean Air Act of 1970 gave the US EPA board authority to regulate motor vehicle pollution and the agencies emission control policies and requirements have become progressively more stringent since then

5 0

3 years ago

Which of the following values represents an index of refraction of an actual material?

Airida [17]

The answer is <em>B. 5/4</em> or <em>1.25</em>

3 0

3 years ago

In one contest at the county fair, a spring-loaded plunger launches a ball at a speed of 3.2m/s from one corner of a smooth, fla

lara31 [8.8K]

Answer:

Explanation:

Given

Speed of ball $u=3.2\ m/s$

Plane is inclined at an angle $20^{\circ}$

To win the Game we need to hit the target at $x=2.4\ m$ away

Launch angle of ball $\theta$

Motion of ball can be considered in two planes i.e. Vertical to the plane and horizontal to the plane

So Net acceleration in vertical plane is $g\sin 20$

Range of Projectile is given by

$R=\frac{u^2\sin 2\theta }{g}$

for $R=2.4\ m$

$2.4=\frac{3.2^2\times sin 2\theta }{g\sin 20}$

$\sin 2\theta =\frac{2.4\times 9.8\times \sin 20}{3.2^2}$

$\sin 2\theta =0.7855$

$2\theta =51.77$

$\theta =25.88^{\circ}$

so ball must be launched at an angle of $25.88^{\circ}$

4 0

3 years ago