All categories

3 years ago

A toy cart moves with a kinetic energy of 30 J. If its speed is doubled, what is its kinetic energy?

Physics

1 answer:

klio [65]3 years ago

8 0

Explanation:

KE is directly proportional to the square of velocity / speed.

if speed is 2 times (doubled) the KE will be

${2}^{2}$

= 4 times the original KE

$4 \times (30)$

$= 120 \: j$

You might be interested in

Find the order of magnitude of your age in seconds

Natali5045456 [20]

The order of magnitude of my age in seconds is 10^9. I think you'll find that this is true for anyone who is 32 or older.

6 0

3 years ago

The main strength and weakness of traditional economy?

olasank [31]

the main strenght is each person has a job and the weekness is they are poor

4 0

3 years ago

An airplane starts from A and flies to B at a constant speed. After reaching B it returns to A at the same speed. There was no w

Dafna1 [17]

Answer:

When there is wind it takes longer

Explanation:

With no wind, the round trip time is

$t_1=\frac{d}{v}+\frac{d}{v}=\frac{2d}{v}$

When we have a constant wind speed w

$t_2=\frac{d}{v-w} +\frac{d}{v+w} =\frac{2vd}{v^{2} -w^{2}}$

comparing the reciprocal times;

$\frac{1}{t_2}=\frac{v^{2}-w^{2} }{2vd}=\frac{v}{2d}-\frac{w^{2}}{2vd} \leq \frac{v}{2d}=\frac{1}{t_1}$

This means that t1 is smaller than t2, ergo, it takes longer with wind

4 0

3 years ago

A speed versus time graph is shown:

erma4kov [3.2K]

In the given graph, from 4.0 s to 8.0 s, the object is at rest because the speed is zero.

In the given graph we can deduce the following;

at the time interval, 0 s to 3.5 s, the speed of the object = 1 cm/s

when the time, t= 4 s, the speed of the object = 0 cm/s

at the time interval, 4.0 s to 8.0 s, the speed of the object = 0 cm/s

When the speed of an object is zero (0), the object is simply at rest.

Thus, we can conclude that in the given graph, from 4.0 s to 8.0 s, the object is at rest because the speed is zero.

Learn more here:brainly.com/question/10454047

6 0

2 years ago

A 0.40-kg mass attached to the end of a string swings in a vertical circle having a radius of 1.8 m. At an instant when the stri

san4es73 [151]

Answer:

T = 8.55 N

Explanation:

When string makes an angle 40 degree with the vertical then it will have two forces on it

1) gravitational force (mg)

2) Tension force in string (T)

now we know that net force towards the center of the path is known as centripetal force and it is given as

$T - mg cos40 = F_c$

$T - (0.40\times 9.8)cos40 = \frac{mv^2}{L}$

$T = 3 + \frac{0.40\times 5^2}{1.8}$

$T = 3 + 5.55$

$T = 8.55 N$

6 0

3 years ago