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3 years ago

7

Một vật dao động điều hòa với phương trình x= 4cos(6πt) cm. Kể từ khi vật bắt đầu dao động, thời điểm vật qua a) vị trí cân bằng

lần thứ 1 là? b) vị trí biên x=4 lần thứ 2 là? c) vị trí x= -2 lần thứ 9 là ? d) vị trí x=2 lần thứ 2020 là?

1 answer:

dezoksy [38]3 years ago

7 0

Answer:

what are you saying.........

......

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Let's examine over the next few questions an NFL kick as described in the 3rd Law video. The announcer claimed that the ball is

hichkok12 [17]

Answer:

8451.62109367671 Newtons

Explanation:

$1\ kg=1\times 9.8066500286389=9.8066500286389\ N$

$1 \lb=2.2046226218488\ kg$

It is known that

$1\ lbs=\dfrac{9.8066500286389}{2.2046226218488}=4.4482216282508\ N$

So,

$1900\ lbs=1900\times 4.4482216282508\\\Rightarrow 1900\ lbs=8451.6210936765\ N$

The force in Newtons is 8451.6210936765 Newtons

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4 years ago

The earth has a radius of 6.38 × 106 m and turns on its axis once every 23.9 h.

Vladimir [108]

Answer:

a) V = 465.9 m/s

b) θ = 70.529°

Explanation:

Let's first calculate angular velocity of earth:

$\omega=\frac{2\pi}{23.9h}*1h/3600s$

Velocity of a person on Ecuador will be:

$V_E = \omega*R$

$V_E = 465.9 m/s$

For part b, since angular velocity is the same:

$\frac{\omega*R}{3}=\omega*(R*cos\theta )$

Solving for θ:

$\theta=acos(1/3)$

$\theta=70.529\°$

8 0

4 years ago

What are two conditions of equilibrium? write them in word

valentina_108 [34]

In order for a system to be in equilibrium , two conditions must be met. Net force must be 0.

6 0

3 years ago

How much work is done if I use 5N of force to move an object 2 meters

sweet-ann [11.9K]

It’s 10 joules. W=FD, W=5•2=10

8 0

3 years ago

Suppose that a simple pendulum consists of a small 81 g bob at the end of a cord of negligible mass. If the angle θ between the

MariettaO [177]

Answer:

(a) 0.115 m

(b) 2.08 x 10^-5 J

Explanation:

mass of bob, m = 81 g = 0.081 kg

The equation of oscillation is given by

θ = 0.068 Cos {9.2 t + Ф}

Now by comparison

The angular velocity

ω = 9.2 rad/s

(a) $\omega^{2} =\frac{g}{L}$

where, L be the length of the pendulum

$L =\frac{g}{\omega ^{2}}$

$L =\frac{9.8}{9.2 \times 9.2}$

L = 0.115 m

(b) A = L Sinθ

A = 0.115 x Sin 0.068

A = 7.8 x 10^-3 m

Maximum kinetic energy

K = 0.5 x mω²A²

K = 0.5 x 0.081 x 9.2 x 9.2 x 7.8 x 7.8 x 10^-6

K = 2.08 x 10^-5 J

8 0

3 years ago