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2 years ago

what is the average speed of (a) a car that travels 400m in 20s. and (b) an athlete who runs 1500m in 4 minutes

Physics

1 answer:

zmey [24]2 years ago

5 0

Answer:

a) 20 m/s

b) 37.5 m)s

Explanation:

Average speed = total distance ÷ total time

=> (a) average speed of a car that travels 400m in 20s

= 400/20 = 20 m/s

& (b) average speed of an athlete who runs 1500m in 4 minutes (or 4×60=240 seconds)

= 1500/240 = 37.5 m/s

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A feather, a marble, and a cannonball are dropped from the same height at

Vika [28.1K]

The correct answer is that they would all hit the ground at the same time. If no air resistance is present, the rate of descent depends only on how far the object has fallen, no matter how heavy the object is. This means that two objects will reach the ground at the same time if they are dropped simultaneously from the same height. This statement follows from the law of conservation of energy and has been demonstrated experimentally by dropping a feather and a lead ball in an airless tube.

7 0

2 years ago

Two balloons are charged with an identical quantity and type of charge: -6.25 x 10-6 C. They are held apart at a separation dist

steposvetlana [31]

Answer:

The electric force between them is 878.9 N

Explanation:

Given:

Identical charge $q = -6.25 \times 10^{-6}$ C

Separation between two charges $r = 0.02$ m

For finding the electrical force,

According to the coulomb's law

$F = \frac{k q^{2} }{r^{2} }$

Here, force between two balloons are repulsive because both charges are same.

Where $k = 9 \times 10^{9}$

$F = \frac{9 \times 10^{9} \times (-6.25 \times 10^{-6} )^{2} }{4 \times 10^{-4} }$

$F = 878.9$ N

Therefore, the electric force between them is 878.9 N

8 0

3 years ago

If a migrating loon flies at an average speed of 19 m/s, what is its average speed in mi/hr?

zlopas [31]

Unit conversion is a way of converting some common units into another without changing their real value. The average speed of the migrating loon flies is 45.5019 miles/hr.

<h3>What is Unit conversion?</h3>

Unit conversion is a way of converting some common units into another without changing their real value. for, example, 1 centimeter is equal to 10 mm, though the real measurement is still the same the units and numerical values have been changed.

Given that migrating loon flies at an average speed of 19 m/s. Now, since 1 meter is equal to (1/1609.34) miles and 1 second is equal to (1/3600) seconds. Therefore, we can write the speed as,

$\rm Speed = 19\ \dfrac{meter}{second}\\$

$=19 \times \dfrac{\frac{1}{1609.34}\rm\ miles}{\frac{1}{3600} \rm\ hours}$

= 19 × (3600/1609.34) miles/hr

= 42.5019 miles/ hr

Hence, the average speed of the migrating loon flies is 45.5019 miles/hr.

Learn more about Units conversion here:

brainly.com/question/4736731

#SPJ4

4 0

8 months ago

A. What is the equation describing the motion of a mass on the end of a spring which is stretched 8.8cm from equilibrium and the

Naddik [55]

Answer:

a) x = 8.8 cm * cos (9.52 rad/s * t)

b) x = 8.45 cm

Explanation:

This is a Simple Harmonic Motion, and most Simple Harmonic Motion equations start from the equilibrium point. In this question however, we are starting from the max displacement the equations, and thus, it ought to be different.

From the question, we are given that

A = 8.8 cm = 0.088 m

t = 0.66 s

Now, we need to find the angular speed w, such that

w = 2π/T

w = (2 * 3.142) / 0.66

w = 6.284 / 0.66

w = 9.52 rad/s

The displacement equation of Simple Harmonic Motion is usually given as

x = A*sin(w*t)

But then, the equation starts from the equilibrium point at 0 sec, i.e x = 0 m

When you have to start from the max displacement, then the equation would be

x = A*cos(w*t).

So when t = 0 the cos(0) = 1, and then x = A which is max displacement.

Thus, the equation is

x = 8.8 cm * cos (9.52 rad/s * t)

At t = 1.7 s,

x = 8.8 cos (9.52 * 1.7)

x = 8.8 cos (16.184)

x = -8.45 cm

5 0

3 years ago

Read 2 more answers

A crane lifts a 425 kg steel beam vertically upward a distance of 614.4 m

Maru [420]

PHYSICS

*not sure about the answer but here we go*

Mass = 425 kg

distance = 614.4 m

acceleration = 1.8 m/s²

Answer :

Count Force first.

$f \: = m \: \times a$

F = 425 × 1,8

F = 765 N ✅

Now let's count Work.

$w \: = \: f \: \times s$

W = 765 × 614.4

W = 470016 J ✅

7 0

2 years ago

what is the average speed of (a) a car that travels 400m in 20s. and (b) an athlete who runs 1500m in 4 minutes​

what is the average speed of (a) a car that travels 400m in 20s. and (b) an athlete who runs 1500m in 4 minutes