Answer:
21
Explanation: its actually 20.85 but i guess they round to 21
Answer:
He could jump 2.6 meters high.
Explanation:
Jumping a height of 1.3m requires a certain initial velocity v_0. It turns out that this scenario can be turned into an equivalent: if a person is dropped from a height of 1.3m in free fall, his velocity right before landing on the ground will be v_0. To answer this equivalent question, we use the kinematic equation:
With this result, we turn back to the original question on Earth: the person needs an initial velocity of 5 m/s to jump 1.3m high, on the Earth.
Now let's go to the other planet. It's smaller, half the radius, and its meadows are distinctly greener. Since its density is the same as one of the Earth, only its radius is half, we can argue that the gravitational acceleration g will be <em>half</em> of that of the Earth (you can verify this is true by writing down the Newton's formula for gravity, use volume of the sphere times density instead of the mass of the Earth, then see what happens to g when halving the radius). So, the question now becomes: from which height should the person be dropped in free fall so that his landing speed is 5 m/s ? Again, the kinematic equation comes in handy:
This results tells you, that on the planet X, which just half the radius of the Earth, a person will jump up to the height of 2.6 meters with same effort as on the Earth. This is exactly twice the height he jumps on Earth. It now all makes sense.
Answer:
D) 763 nm
Explanation:
Calculation for the wavelength of light
Using this formula
Wavelength of light=Delta Y*Distance / Length
Where,
Delta Y represent the 2nd order bright fringe
Length represent the distance between both the slits and the screen
Distance represent the Distance between the slits
Let note that cm to m = (4.2) x 10^-2 and mm to m= ( 0.0400x 10^-3)
Now Let plug in the formula
Wavelength of light=[(4.2 x 10^-2m)(0.0400 x 10^-3m) / 2(1.1m)]*10^-7 meters
Wavelength of light=[(0.042m) (0.0004m)/2.2m]*10^-7 meters
Wavelength of light =(0.0000168m/2.2m)*10^-7 meters
Wavelength of light =7.63 *10^-7 meters
Wavelength of light =763 nm
Therefore the Wavelength of light will be 763 nm
Answer:
1) In a concave mirror parallel rays falling on it converges at F and 2F.
Explanation:
Spherical mirrors can be used for magnification of images. There are basically two types of spherical mirrors and they are converging mirror and diverging mirrors. The converging mirrors are also termed as concave mirrors and its basic work is to converge or combine light rays coming from a larger distance to a single point. Mostly the light beams falling parallel to the principle axis of the concave mirror will be acting as parallel rays. And when these parallel rays fall on the mirror, the converging point can be the focal point of the mirror.
Thus the location of converging point in concave mirrors will be based on the position or distance of object from the mirror. If the object distance is very far from the twice the focal length distance of mirror, then the converging point will be the focal point or F. And if the object is placed slightly greater than twice the distance of focal point, then the image will be obtained at 2F. But the parallel beams will be converging at F and 2F.
