All categories

3 years ago

HELP MEEEEEEEE PLEASEEEE

Physics

1 answer:

Lemur [1.5K]3 years ago

5 0

Answer:

B Explain why the relationship between force and time is important to a helmet designer.

During a collision, a skater will suddenly come to a complete stop. This is a foam of acceleration. A helmet can change the amount of

hope you get a good grade

You might be interested in

Which best describes how combustion works?

jekas [21]

The answer is A, it breaks down and releases thermal energy.

3 0

3 years ago

Read 2 more answers

A plastic film moves over two drums. During a 4-s interval the speed of the tape is increased uniformly from v0 = 2ft/s to v1 =

Ratling [72]

Answer:

Question 1)

a) The speed of the drums is increased from 2 ft/s to 4 ft/s in 4 s. From the below kinematic equations the acceleration of the drums can be determined.

$v_1 = v_0 + at \\4 = 2 + 4a\\a = 0.5~ft/s^2$

This is the linear acceleration of the drums. Since the tape does not slip on the drums, by the rule of rolling without slipping,

$v = \omega R\\a = \alpha R$

where α is the angular acceleration.

In order to continue this question, the radius of the drums should be given.

Let us denote the radius of the drums as R, the angular acceleration of drum B is

α = 0.5/R.

b) The distance travelled by the drums can be found by the following kinematics formula:

$v_1^2 = v_0^2 + 2ax\\4^2 = 2^2 + 2(0.5)x\\x = 12 ft$

One revolution is equal to the circumference of the drum. So, total number of revolutions is

$x / (2\pi R) = 6/(\pi R)$

Question 2)

a) In a rocket propulsion question, the acceleration of the rocket can be found by the following formula:

$a = \frac{dv}{dt} = -\frac{v_{fuel}}{m}\frac{dm}{dt} = -\frac{13000}{2600}25 = 125~ft/s^2$

b) $a = -\frac{v_{fuel}}{m}\frac{dm}{dt} = - \frac{13000}{400}25 = 812.5~ft/s^2$

5 0

3 years ago

IP The x and y components of a vector r⃗ are rx = 16 m and ry = -8.5 m , respectively

fiasKO [112]

as it is given that

$r_x = 16 m$

$r_y = -8.5 m$

now we will have

$\vec r = 16 \hat i - 8.5 \hat j$

now the magnitude of this vector is given as

$|r| = \sqrt{16^2 + 8.5^2}$

$|r| = 18 m$

now to find the direction we can use

$tan\theta = \frac{r_y}{r_x}$

$tan\theta = \frac{-8.5}{16}$

$\theta = tan^{-1}(-0.53)$

$\theta = - 28^0$

4 0

4 years ago

Amanda has started running as her primary form of exercise, but she's getting bored with it and finds excuses to procrastinate.

blsea [12.9K]

AnswerB

Explanation:

Just get good

KIDDDDDD

4 0

2 years ago

Read 2 more answers

Describe some tests that could be done to determine what an unknown substance is.

natima [27]

Answer:

by finding melting and boiling points

Explanation:

3 0

3 years ago

Read 2 more answers