How far should pencil held from a convex mirror of radius 80 cm to form an image one-half the size of the pencil?

An air craft heads north at 320 km/hr relative to the wind. the wind velocity is 80km/hr from the north. find the relative veloc

Gnoma [55]

Answer:

Relative to the ground, the velocity of the aircraft is 240 km/hr

Explanation:

Relative velocity is different from normal velocity;

When 2 objects are moving in opposite directions towards each other, they will appear to be faster than they actually are;

This is known as the relative velocity;

The information tells us we have the aircraft moving 320 km/hr northwards relative to the wind;

The wind is in the opposite direction at 80 km/hr;

R = relative velocity of the aircraft

v = actual velocity of the aircraft

w = velocity of the wind

R = v + w

Note: if the wind was moving in the same direction, the formula would be R = v - w

320 = v + 80

v = 320 - 80

v = 240

The velocity relative to the ground is simply the actual velocity as the ground doesn't move;

So, relative to the ground, the velocity of the aircraft is simply 240 km/hr

7 0

3 years ago

5. A family leaves for an evening walk around the neighborhood. They leave at 5 pm and return at 6 pm. They traveled a total of

vlabodo [156]

This question involves the concepts of average speed, distance, and time.

The average speed of the family is "2.5 mi/hr".

<h3>AVERAGE SPEED</h3>

The average speed is defined as the ratio of the total distance covered with the total time taken to cover it.

$v=\frac{s}{t}$

where,

s = distance covered = 2.5 miles
t = total time taken = 1 hour
v = average speed = ?

Therefore,

$v=\frac{2.5\ mi}{1\ hr}$

v = 2.5 mi/hr

Learn more about average speed here:

brainly.com/question/12322912

4 0

2 years ago

Explain why a 10 kg stone and 1 kg stone dropped from the same height

11111nata11111 [884]

The acceleration of a body in a gravitational field is independent of its mass. Both the stones will fall with the same acceleration through the same height and hence they will strike the ground simultaneously.
GIVE ME POINTS

3 0

3 years ago

Two loudspeakers emit 600 Hz Hz notes. One speaker sits on the ground. The other speaker is in the back of a pickup truck. You h

Firdavs [7]

Answer:

The truck's speed is 4.04 m/s.

Explanation:

Given that,

Emit frequency = 600 Hz

Beat = 7.00 beat/sec

We need to calculate the truck's speed

Using formula of speed

$\text{frequency observed}=\text{frequency emitted}\times\dfrac{v}{v+v_{source}}$

Where, v = speed of sound

Put the value into the formula

$(600-7)=600\times(\dfrac{343}{343-v_{truck}})$

$v_{truck}=\dfrac{600\times343-593\times343}{593}$

$v_{truck}=4.04\ m/s$

Hence, The truck's speed is 4.04 m/s.

3 0

3 years ago

A tree moves at 30 km/s relative to the Sun. A squirrel jumps from a branch on

tresset_1 [31]

The reasoning is wrong if we look into Newton's Law of gravitation.

Newton's law of gravitation states that every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

The law is written as follows;

$F = \frac{Gm_1m_2}{r^2}$

$r = \sqrt{\frac{Gm_1m_2}{F} }$

The distance between the two particles, is a function of force and their masses not necessarily time of motion.

In the given problem only time of motion was considered which is wrong.

Thus, the reasoning is wrong if we look into Newton's Law of gravitation.

Learn more here: brainly.com/question/19680441

7 0

3 years ago