All categories

2 years ago

Someone help please i need to finish this

Physics

1 answer:

Tom [10]2 years ago

6 0

Answer:

4th answer

Explanation:

The gradient of a distance-time graph gives the speed.

gradient = distance / time = speed

Here, the gradient is a constant till 30s. So it has travelled at a constant speed. It means it had not accelarated till 30s. and has stopped moving at 30s.

You might be interested in

An airplane travels 1200 km in 90 minutes. What is the average speed in m/s for this trip?

gladu [14]

Answer:

the answer is 1333.33m/s

3 0

3 years ago

When you jump, you exert a pushing force against the ground. Gravity pulls you back down. Why can a person jump higher on the mo

Dennis_Churaev [7]

Answer:

This is because the force of gravity is much less on the moon than on the earth, therefore the person wont be pulled down much and will jump higher

7 0

3 years ago

Help please, I don't get it

Sergio [31]

Answers:

a) $\hat F=(0.83,-0.55) N$

b) $\hat D=(-0.44,-0.89) m$

c) $\hat V=(-0.47,0.88) m/s$

Explanation:

A unit vector is a vector whose magnitude (length) is equal to 1. This kind of vector is identified as $\hat v$ and the way to calculate is as follows:

$\hat v=\frac{\vec v}{|v|}$

Where:

$\vec v=(x,y)$ is the vector

$|v|=\sqrt{x^{2}+y^{2}}$ is the magnitude of the vector

Having this information clarified, let's begin with the answers:

a) Force Vector

$\vec F=(9.0 \hat i - 6.0 \hat j) N$

Magnitude of $\vec F$ :

$|F|=\sqrt{(9.0 \hat i)^{2}+(-6.0 \hat j)^{2 }}N=10.81 N$

Unit vector:

$\hat F=\frac{\vec F}{|F|}$

$\hat F=\frac{(9.0 \hat i - 6.0 \hat j) N}{10.81 N}$

$\hat F=\frac{9.0}{10.81} N-\frac{6.0}{10.81}N$

$\hat F=(0.83,-0.55) N$

b) Displacement Vector

$\vec D=(-4.0 \hat i - 8.0 \hat j) m$

Magnitude of $\vec D$ :

$|D|=\sqrt{(-4.0 \hat i)^{2}+(-8.0 \hat j)^{2 }}m=8.94 m$

Unit vector:

$\hat D=\frac{\vec D}{|D|}$

$\hat D=\frac{(-4.0 \hat i - 8.0 \hat j) m}{8.94 m}$

$\hat D=\frac{-4.0}{8.94} Nm+\frac{-8.0}{8.94}m$

$\hat D=(-0.44,-0.89) m$

c) Velocity Vector

$\vec V=(-3.50 \hat i + 6.50 \hat j) m/s$

Magnitude of $\vec V$ :

$|V|=\sqrt{(-3.50 \hat i)^{2}+(6.50 \hat j)^{2}}m/s=7.38 m/s$

Unit vector:

$\hat V=\frac{\vec V}{|V|}$

$\hat V=\frac{(-3.50 \hat i +6.50 \hat j) m/s}{7.38 m/s}$

$\hat V=\frac{-3.50}{7.38} m/s+\frac{6.50}{7.38}m/s$

$\hat V=(-0.47,0.88) m/s$

8 0

4 years ago

relationship beetween image distance,focal length ,power magnification, for both concave and convex lens.

scoray [572]

Answer:

Object distance means what is the distance between pole and object. Image distance means when image is formed then the distance between pole and image is called image distance. Focal length is the distance between pole and the principal focus of the mirror.

A lens is a clear object, usually made of glass or plastic, which is used to refract, or bend light. Lenses can concentrate light rays (bring them together) or spread them out. Common examples of lenses include camera lenses, telescope lenses, eyeglasses, and magnifying glasses. Lenses are often double lenses, meaning they have two curved sides. A convex lens is rounded outward, while a concave lens curves inward. (A great way to remember this is that a concave lens creates an indent like a cave!)

The image distance can be calculated with the knowledge of object distance and focal length with the help of lens formula. In optics, the relationship between the distance of an image (i), the distance of an object (o), and the focal length (f) of the lens are given by the formula known as Lens formula. Lens formula is applicable for convex as well as concave lenses. These lenses have negligible thickness. It is an equation that relates the focal length, image distance, and object distance for a spherical mirror. It is given as,

1/i + 1/o = 1/f

i= distance of the image from the lens

o= distance of the object from the lens

f= focal length of the lens

Explanation:

Hope it is helpful....