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2 years ago

If you are about to be hit from behind, your best course of action is to brake gently and stop the car.

1 answer:

8 0

ANSWER: B. False

Stopping when there is a speeding car about to hit you from behind would be the most illogical thing to do as this would increase the impact of collision. This is because you will certainly be propelled forwards with a speed as fast as the car behind you. This is according to the concept of momentum and collisions.

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What is the condition for an object experiencing free fall?

S_A_V [24]

Answer:

The body acts under the influence of gravity.

Explanation:

An object experiencing free fall is acting under the influence of gravitational force and the acceleration due gravity is positive for any falling object. The body is able to fall freely due to the effect of gravity on it. This gravity effect causes the body to get attracted to the earth's gravitational surface due to gravitational pull exerted on the body.

3 0

3 years ago

A skateboarder flies horizontally off a cement planter. After 3 seconds the skateboarder lands on the ground with a final veloci

evablogger [386]

Given the time, the final velocity and the acceleration, we can calculate the initial velocity using the kinematic equation A:

$v = v_o + a \Delta t$

A skateboarder flies horizontally off a cement planter. After a time of 3 seconds (Δt), he lands with a final velocity (v) of −4.5 m/s. Assuming the acceleration is -9.8 m/s² (a), we can calculate the initial velocity of the skateboarder (v₀) using the kinematic equation A.

$v = v_o + a \Delta t\\\\v_o = v - a \Delta t = (-4.5 m/s) - (-9.8 m/s^{2} ) \times 3 s = 24.9 m/s$

Given the time, the final velocity and the acceleration, we can calculate the initial velocity using the kinematic equation A:

$v = v_o + a \Delta t$

Learn more: brainly.com/question/4434106

3 0

2 years ago

A camera takes a properly exposed photo with a 4.0 mm diameter aperture and a shutter speed of 1/1000 s. If the photographer foc

hoa [83]

Answer:

option E

Explanation:

given,

diameter = 4 mm

shutter speed = 1/1000 s

diameter of aperture = ?

shutter speed = 1/250 s

exposure time to the shutter time

$E V = log_2(\dfrac{N^2}{t})$

N is the diameter of the aperture and t is the time of exposure

now,

$log_2(\dfrac{N^2}{t_1})=log_2(\dfrac{N^2}{t_2})$

$\dfrac{N_1^2}{t_1}=\dfrac{N_2^2}{t_2}$

inserting all the values

$\dfrac{4^2}{1000}=\dfrac{N_2^2}{250}$

N₂² = 4

N₂ = 2 mm

hence , the correct answer is option E

4 0

3 years ago

if you run around a circle at 4.5 m/s and the circle has a radius of 7.7 m, what is your centripetal acceleration?

madreJ [45]

Answer:

Centripetal acceleration,

$a_{c} =2.63\ m/s^{2} }$

Explanation:

Centripetal acceleration:

Centripetal acceleration is the idea that any object moving in a circle, in something called circular motion, will have an acceleration vector pointed towards the center of that circle.

Centripetal means towards the center.

Examples of centripetal acceleration (acceleration pointing towards the center of rotation) include such situations as cars moving on the cicular part of the road.

An acceleration is a change in velocity.

Formula for Centripetal acceleration:

$a_{c} =\frac{(velocity)^{2} }{radius}$

Given here,

Velocity = 4.5 m/s

radius = 7.7 m

To Find :

$a_{c} = ?$

Solution:

We have,

$a_{c} =\frac{(velocity)^{2} }{radius}$

Substituting given value in it we get

$a_{c} =\frac{(4.5)^{2}}{7.7} \\\\a_{c} =\frac{20.25}{7.7}\\\\a_{c} =2.629\ m/s^{2} \\\\\therefore a_{c} =2.63\ m/s^{2$

Centripetal acceleration,

$a_{c} =2.63\ m/s^{2} }$

7 0

3 years ago

What are the two roles of bacteria in the nitrogen cycle?

Arisa [49]

Answer:

1. Where they multiply and stimulate formation of root nodules.

2. Enlargements of plant cells and bacteria in intimate association.

4 0

2 years ago