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3 years ago

zeros are always considered significant digits when they are to the left of the decimal point True or False

Physics

2 answers:

zlopas [31]3 years ago

8 0

Answer:

false

Explanation:

because they does'nt Work for anything, are like they are not there

Hunter-Best [27]3 years ago

4 0

Answer:

False

Explanation:

The rules for significant figures are:

Non-zero digits are always significant.
Zeros between significant digits are also significant.
Trailing zeros are significant only after a decimal point.

A zero before a decimal point is only significant if there's a non-zero digit before it.

For example, in the number 10.5, the zero is significant, because it is between significant digits.

But in the number 0.5, the zero is not significant.

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A 10 kg monkey climbs up a massless rope that runs over a frictionless tree limb and back down to a 15 kg package on the ground.

pshichka [43]

Answer:

A. 4,9 m/s2

B. 2,0 m/s2

C. 120 N

Explanation:

In the image, 1 is going to represent the monkey and 2 is going to be the package. Let a_mín be the minimum acceleration that the monkey should have in the upward direction, so the package is barely lifted. Apply Newton’s second law of motion:

$\sum F_y=m_1*a_m_i_n = T-m_1*g$

If the package is barely lifted, that means that T=m_2*g; then:

$\sum F_y =m_1*a_m_i_n=m_2*g-m_1*g$

Solving the equation for a_mín, we have:

$a_m_i_n=((m_2-m_1)/m_1)*g = ((15kg-10kg)/10kg)*9,8 m/s^2 =4,9 m/s^2$

Once the monkey stops its climb and holds onto the rope, we set the equation of Newton’s second law as it follows:

For the monkey: $\sum F_y = m_1*a \rightarrow T-m_1*g=m_1*a$

For the package: $\sum F_y = m_2*a \rightarrow m_2*g - T = m_2*a$

The acceleration a is the same for both monkey and package, but have opposite directions, this means that when the monkey accelerates upwards, the package does it downwards and vice versa. Therefore, the acceleration a on the equation for the package is negative; however, if we invert the signs on the sum of forces, it has the same effect. To be clearer:

For the package: $\sum F_y = -m_2*a \rightarrow T-m2*g=-m_2*a \rightarrow m_2*g -T=m_2 *a$

We have two unknowns and two equations, so we can proceed. We can match both tensions and have:

$m_1*a+m_1*g=m_2*g-m_2*a$

Solving a, we have

$(m_1+m_2)*a =(m_2 - m1)*g\\\\a=((m_2-m_1)/(m_1+m_2))*g \rightarrow a=((15kg-10kg)/(10kg+15kg))*9,8 m/s^2\\\\a= 2,0 m/s^2$

We can then replace this value of a in one for the sums of force and find the tension T:

$T = m_1*a+m_1*g \rightarrow T=m_1*(a+g)\\\\T = 10kg*(2,0 m/s^2+9,8 m/s^2) \\\\T = 120 N$

5 0

3 years ago

Which of the following is characteristic of proficient catching?

uysha [10]

Answer:

The correct answer is option D i.e. A and C

Explanation:

The correct answer is option D i.e. A and C

for proficient catching player must

- learn to absorbed the ball force

- moves the hang according to ball direction to hold the ball

- to catch ball at high height move the finger at higher position

- to catch ball at low height move the finger at lower position

5 0

3 years ago

Choose all the answers that apply.

spin [16.1K]

Answer:

B and C?

Explanation:

3 0

3 years ago

Two equal forces are applied to a door. The first force is applied at the midpoint of the door, the second force is applied at t

Orlov [11]

Answer:

D) the second at the doorknob

Explanation:

The torque exerted by a force is given by:

$\tau = Fdsin \theta$

where

F is the magnitude of the force

d is the distance between the point of application of the force and the centre of rotation

$\theta$ is the angle between the direction of the force and d

In this problem, we have:

- Two forces of equal magnitude F

- Both forces are perpendicular to the door, so $\theta=90^{\circ}, sin \theta=1$

- The first force is exerted at the midpoint of the door, while the 2nd force is applied at the doorknob. This means that d is the larger for the 2nd force

--> therefore, the 2nd force exerts a greater torque

4 0

3 years ago

The relationship between linear velocity and angular velocity

bonufazy [111]

In linear motion , when a body moves with uniform velocity , in time t , its linear displacement will be ;

S = r∅ S = vt

r∅ = vt

r.∅ / t = v

v = rw

where ∅ = 90° is the angle between between radius vector r and angular velocity w (omega )

In case ∅ ≠ 90° , we can write v = r w sin∅

It gives us v = w× r

7 0

3 years ago