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1 year ago

A rock falls off a cliff. How fast will it be going after falling for 4.33 seconds?

Physics

1 answer:

bixtya [17]1 year ago

4 0

Answer:42.43m/s

Explanation:According to vf=vi+at, we can calculate it since v0 equals to 0. vf=0+9.8m/s^2*4.33s= 42.434m/s

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A negatively charged rod is brought near a neutral metal sphere. Which of the following is true? A negatively charged rod is bro

Yuki888 [10]

Answer:

There is an attractive force between the rod and sphere.

Explanation:

When negatively charged rod is placed close to the metal sphere then due to the electric field of the rod the opposite free charge of metal sphere comes closer to the rod on one surface

While similar charge in the metal sphere move away from the rod due to repulsion of electric field of rod

This temporary charge distribution of the metal sphere is known as induction

And since opposite charge on the metal surface comes closer to the metal sphere so here we can say that the rod will attract the metal sphere

so here correct answer will be

There is an attractive force between the rod and sphere.

3 0

3 years ago

Read 2 more answers

What is the average velocity of a rocket that travels 15 m in 0.25 seconds?

Brrunno [24]

Answer:

60 m/s

Explanation:

Average Speed = Distance/ Time

= 15/0.25 = 60m/s

5 0

4 years ago

The purpose of a cell (battery) is to: Question 2 options: store chemical energy and transfer it to thermal energy when a circui

xz_007 [3.2K]

Answer:

Store chemical energy and transfer it to electrical energy when a circuit is connected.

Explanation:

A battery (single cell) is a container made of one cell that can produce a particular amount of electrical energy when needed.

It works by converting chemical energy to electric energy which is then used as a power source.

It stores up chemical energy and when connected to an external circuit, it provides electrical energy (through the flow of electrical current) to the circuit.

A battery is usually made up of a positive electrode and a negative electrode.

6 0

3 years ago

Any 5 points about importance of si system

grin007 [14]

Answer:

SI unit is an international system of measurements that are used universally in technical and scientific research to avoid the confusion with the units. Having a standard unit system is important because it helps the entire world to understand the measurements in one set of unit system. i hope this helps

Explanation:

7 0

3 years ago

12*3a car is stopped at a traffic light. it then travels along a straight road so that its distance from the light is given by w

Digiron [165]

Missing parts in the text of the exercise:
- The distance from the traffic light is given by $x(t) = bt^2 -ct^3$ , where $b=2.4 m/s^2$ and $c=0.13 m/s^3$

Solution:

part a) calculate the average velocity of the car for the time interval t=0 to t=8.0 s
- The average velocity is given by the ratio between the distance covered in the time interval:
 $v_{ave} = \frac{x(8.0 s)-x(0 s)}{8.0 s-0 s}$
x(0 s), the distance covered after t=0 s, is zero, while the distance after t=8.0 s is
$x(8.0 s)=b(8 s)^2-c(8 s)^3 = (2.4 m/s^2)(8 s)^2 -(0.13 m/s^3)(8 s)^3=$
$=87.04 m$
Therefore, the average velocity is
$v_{ave}= \frac{x(8.0 s)-x(0)}{8.0s-0}= \frac{87.04 m}{8.0s}= 10.88 m/s$

part b) calculate the instantaneous velocity of the car at t=0, t=4.0 s and t=8.0 s
- The instantaneous velocity can be found by performing the derivation of x(t):
 $v(t) = \frac{dx(t)}{dt}=2bt-3ct^2$
So now we just have to substitute t=0, t=4 s and t=8 s:
- t=0: v(0)=0
- t=4 s: $v(4.0 s)=2(2.4 m/s^2)(4.0 s)-3(0.13 m/s^2)(4.0s)^2=12.96 m/s$
- t=8 s: $v(8.0 s)=2(2.4 m/s^2)(8.0 s)-3(0.13 m/s^2)(8.0s)^2=13.44 m/s$

part c) how long after starting from rest is the car again at rest?
- To solve this part we must find the value of t for which v(t)=0, so:
 $2bt-3ct^2=0$
$t(2b-3ct)=0$
The first solution is t=0 s, which corresponds to the beginning of the motion, so we are not interested in this value. The second solution is
 $t= \frac{2b}{3c}= \frac{2\cdot 2.4 m/s^2}{3 \cdot 0.13 m/s^3}=12.31 s$
and this is the time at which the car is at rest again.

8 0

3 years ago