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oksano4ka [1.4K]

3 years ago

13

A spring has a spring constant of 55 N/m. How much energy is stored in the spring when it is compressed 0.3 m past it's natural

length?

2 answers:

mixer [17]3 years ago

6 0

E = 0.5kx² = 0.5 * 55 * 0.3² = 2.475

Sladkaya [172]3 years ago

5 0

Answer: 2.5 J

Explanation:

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A rock is suspended from a string, and it accelerates downward. Which one of the following statements is correct? Group of answe

Tems11 [23]

Answer:

a. The magnitude of the tension in the string is greater than the magnitude of the weight of the rock.

Explanation:

During the motion of the rock while it is in downward motion we can say

$T - mg cos\theta = ma_c$

since it is performing circular motion so we will have its acceleration towards its center

$T = mgcos\theta + ma_c$

$a_c = \frac{v^2}{L}$

$T = mgcos\theta + \frac{mv^2}{L}$

So at the lowest point of the path we can say

$T = mg + \frac{mv^2}{L}$

so correct answer is

a. The magnitude of the tension in the string is greater than the magnitude of the weight of the rock.

4 0

3 years ago

You have landed on an unknown planet, newtonia, and want to know what objects will weigh there. you find that when a certain too

AleksandrR [38]

Refer to the diagram shown.

Because the surface is frictionless, the resistive for, R, is zero.

Let m = the mass of the object.
Let a = acceleration due to the applied force.
Therefore
12.7 N = (m kg)*(a m/s²)
a = 12.7/m m/s²

The object travels 16.1 m in 2.5 s, starting from rest. Therefore
16.1 N = (1/2)*(12.7/m m/s²)*(2.5 s)² = 39.6875/m N
m = 16.1/39.6875 = 0.4057 kg

For freefall, let g = acceleration due to gravity.
The time to fall from 10.3 m is 2.88 s, therefore
10.3 m = (1/2)*(g m/s²)*(2.88 s)² = 4.1472g m
g = 10.3/4.1472 = 2.484 m/s²

Answer:
The gravitational acceleration on the planet is 2.5 m/s² (nearest tenth)

3 0

3 years ago

A body moves in a straight line. At time, it's acceleration is given by a = 12t + 1. When t =0, the velocity of the body v is 2

madreJ [45]

Answer:

v = 6t² + t + 2, s = 2t³ + ½ t² + 2t

59 m/s, 64.5 m

Explanation:

a = 12t + 1

v = ∫ a dt

v = 6t² + t + C

At t = 0, v = 2.

2 = 6(0)² + (0) + C

2 = C

Therefore, v = 6t² + t + 2.

s = ∫ v dt

s = 2t³ + ½ t² + 2t + C

At t = 0, s = 0.

0 = 2(0)³ + ½ (0)² + 2(0) + C

0 = C

Therefore, s = 2t³ + ½ t² + 2t.

At t = 3:

v = 6(3)² + (3) + 2 = 59

s = 2(3)³ + ½ (3)² + 2(3) = 64.5

5 0

3 years ago

How do you find the normal force here? I forgot

kakasveta [241]

Normal force is mass x gravity, so mass x 9.81

6 0

3 years ago

Read 2 more answers

If a stone is dropped from a height of 400 feet, its height after t seconds is given by s = 400 − 16t2. Find its instantaneous v

soldier1979 [14.2K]

Answer:

$v = -32 t$

Explanation:

given,

s = 400- 16 t²

we know,

Velocity of an object is defined as the change in displacement per unit change in time.

velocity an also be return as

$v = \dfrac{ds}{dt}$

$v = \dfrac{d}{dt}(400-16t^2)$

$v= 0 -2\times 16 t$

$v = -32 t$

Hence, instantaneous velocity function given by $v = -32 t$

To calculate instantaneous velocity, you need to insert value of time.

ex, instantaneous velocity at t = 4 s

v = -32 x 4 = -128 m/s.

5 0

3 years ago