All categories

3 years ago

PLEASE HELP:::

Physics

2 answers:

vladimir1956 [14]3 years ago

6 0

Newton's first law of motion is often stated as

<span>An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. Therefore, the answer here is A) Newton's First Law.

Hope this helped ;)
</span>

OleMash [197]3 years ago

6 0

A). Newtons first Law

You might be interested in

A basketball player jumped straight up to grab a rebound. If she was in the air for 0.80 second, how high did she jump?

Kazeer [188]

-- She went up for 0.4 sec and down for 0.4 sec.

-- The vertical distance traveled in gravity during ' t ' seconds is

   D = (1/2) x (g) x (t)²

   = (1/2) (9.8 m/s²) (0.4 sec)²

   = (4.9 m/s²) x (0.16 s²)

   = 0.784 meter ( B )

4 0

3 years ago

Read 2 more answers

The height of a typical playground slide is about 1.8 m and it rises at an angle of 30 ∘ above the horizontal.

Salsk061 [2.6K]

Answer:

$5.94\ \text{m/s}$

$1.7$

$0.577$

Explanation:

g = Acceleration due to gravity = $9.81\ \text{m/s}^2$

$\theta$ = Angle of slope = $30^{\circ}$

v = Velocity of child at the bottom of the slide

$\mu_k$ = Coefficient of kinetic friction

$\mu_s$ = Coefficient of static friction

h = Height of slope = 1.8 m

The energy balance of the system is given by

$mgh=\dfrac{1}{2}mv^2\\\Rightarrow v=\sqrt{2gh}\\\Rightarrow v=\sqrt{2\times 9.81\times 1.8}\\\Rightarrow v=5.94\ \text{m/s}$

The speed of the child at the bottom of the slide is $5.94\ \text{m/s}$

Length of the slide is given by

$l=h\sin\theta\\\Rightarrow l=1.8\sin30^{\circ}\\\Rightarrow l=0.9\ \text{m}$

$v=\dfrac{1}{2}\times5.94\\\Rightarrow v=2.97\ \text{m/s}$

The force energy balance of the system is given by

$mgh=\dfrac{1}{2}mv^2+\mu_kmg\cos\theta l\\\Rightarrow \mu_k=\dfrac{gh-\dfrac{1}{2}v^2}{gl\cos\theta}\\\Rightarrow \mu_k=\dfrac{9.81\times 1.8-\dfrac{1}{2}\times 2.97^2}{9.81\times 0.9\cos30^{\circ}}\\\Rightarrow \mu_k=1.73$

The coefficient of kinetic friction is $1.7$ .

For static friction

$\mu_s\geq\tan30^{\circ}\\\Rightarrow \mu_s\geq0.577$

So, the minimum possible value for the coefficient of static friction is $0.577$ .

8 0

2 years ago

If we want to describe work , we must have what ?

ivanzaharov [21]

An external force that is being applied in the direction of the displacement

4 0

3 years ago

A/ Can someone help me, how can the third law of motion (Newton) help solve a problem / issue. be specific

mezya [45]

/////////////////////////////////////////////////

sorry this is by accident, but i can't delete it

6 0

2 years ago

A ball is dropped from the top of a cliff. By the time it reaches the ground, all the energy in its gravitational potential ener

gogolik [260]

U = mgh, Ek = 1/2*m*v^2

U = Ek (conservation of mechanical energy)

⇒ mgh = 1/2*m*v^2

∵g = 10, v = 20

⇒ 10h = 1/2*400

⇒ h = 20 (m)

4 0

2 years ago