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3 years ago

Choose whether each of the following statements is true or false

Physics

1 answer:

kow [346]3 years ago

6 0

Answer:

1. The statement is false.

2. The statement is false.

Explanation:

1. When a ball is thrown vertically up, the air drag is acting downwards which reduces the time the ball spends traveling upwards, but the air drag is acting upwards while the ball is falling, which increases the time the ball spends traveling downwards.

Thus, the statement is false.

2. The potential energy of a particle is given by

$V = mgh$

where, $m$ is the mass of the object, $g$ is the acceleration due to gravity and $h$ is the vertical height traveled by the object.

It does not depend on th initial velocity of the object.

Thus, the statement is false.

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"Force is applied to an object and the object is moved over a distance in the same direction of the applied force" is the defini

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I believe this is gravitational force

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How can we protect space shuttles or astronauts from space radiation in the absence of the atmospheric layer?

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3 years ago

What specific structures are in electroreceptors?

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3 years ago

A speeding motorist traveling down a straight highway at 100 km/h passes a parked police car. It takes the police constable 1.0

Lubov Fominskaja [6]

Answer:

t = 7.5 s

Explanation:

The distance traveled by the car at the time of meeting of the two cars must be the same. First, we calculate the distance traveled by the police car. For that we use 2nd equation of motion. Here, we take the time when police car starts to be reference. So,

s₁ = Vi t + (0.5)gt²

where,

s₁ = distance traveled by police car

Vi = Initial Velocity = 0 m/s

t = time taken

Therefore,

s₁ = (0 m/s)(t) + (0.5)(9.8 m/s²)t²

s₁ = 4.9 t²

Now, we calculate the distance traveled by the car. For constant speed and time to be 1 second more than the police car time, due to car starting time, we get:

s₂ = Vt = V(t + 1)

where,

s₂ = distance traveled by car

V = Velocity of car = (100 km/h)(1000 m/1 km)(1 h/ 3600 s) = 27.78 m/s

Therefore,

s₂ = 27.78 t + 27.78

Now, we know that at the time of meeting:

s₁ = s₂

4.9 t² = 27.78 t + 27.78

4.9 t² - 270.78 t - 27.78 = 0

solving the equation and choosing the positive root:

t = 6.5 s

since, we want to know the time from the moment car crossed police car. Therefore, we add 1 second of starting time in this.

t = 6.5 s + 1 s

6 0

3 years ago

In order for an external force to do work on a system, Question 9 options: a) there must be a component of the force perpendicul

zepelin [54]

Answer:

b) there must be a component of force parallel to the motion of the object.

Explanation:

We know that work done on a body by an external force is calculated by the formula given below:

W = F.d = Fd Cos θ

where,

W = Work Done by the force on the body

F = Magnitude of force

d = displacement of the body

θ = The angle between the direction of motion of the body and the force applied

It is clear from the formula of the work done, that "F Cosθ" represents the component of the force, that is acting in the direction of motion of the object or parallel to the direction of motion of the object. So, if there is no component of force parallel to motion of object, then this factor will become zero. As a result, the work done will also be zero.

Therefore, the correct option will be:

b) <u>there must be a component of force parallel to the motion of object.</u>

6 0

3 years ago