A body completes 20 revolution in 5sec calculate time period and frequency.

You want to move a 4- kg bookcase to a different place in the living room. If u push with a force of 65 n and the bookcase accel

IrinaK [193]

Answer:

1.65

Explanation:

The equation of the forces along the horizontal direction is:

$F-F_f = ma$ (1)

where

F = 65 N is the force applied with the push

$F_f$ is the frictional force

m = 4 kg is the mass

$a=0.12 m/s^2$ is the acceleration

The force of friction can be written as $F_f = \mu R$ (2), where

$\mu$ is the coefficient of kinetic friction

R is the normal force exerted by the floor

The equation of forces along the vertical direction is

$R-mg=0$ (3)

since the bookcase is in equilibrium. Substituting (2) and (3) into (1), we find

$F-\mu mg = ma$

And solving for $\mu$ ,

$\mu = \frac{F-ma}{mg}=\frac{65-(4)(0.12)}{4(9.8)}=1.65$

7 0

2 years ago

Let the four horizontal compass directions north, east, south, and west be represented by units vectors n^, e^, s^, and w^, resp

Marrrta [24]

Answer:

c = e > b = d > a

Explanation:

Given vectors are all unit vectors, therefore they have a magnitude of 1

<h3>Let a, b be two vectors and magnitude of cross product of these two vectors is (magnitude of a) × (magnitude of b) × (sine of angle between these two vectors)</h3>

As all are unit vectors their magnitude is 1 and therefore in this case the cross product between any two vectors depends on the sine of angle between those two vectors

In option a as both the vectors are same, the angle between them will be zero and sin0° will also be 0

In option b angle between those two vectors is 135° and sin135° is 1 ÷ √2

In option c angle between those two vectors is 90° and sin90° is 1

In option d angle between those two vectors is 45° and sin45° is 1 ÷ √2

In option e angle between those two vectors is 90° and sin90° is 1

So by comparison of magnitudes of cross products in each option, the order will be c = e > b = d > a

5 0

2 years ago

9. True or false. Training at high altitudes can also increase the amount of

Westkost [7]

False because when the training higher there is less oxygen

5 0