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mariarad [96]
3 years ago
11

Which statement correctly describes momentum? It is a scalar quantity because it involves magnitude only. It is a scalar quantit

y because it involves magnitude and direction. It is a vector quantity because it involves magnitude and direction. It is a vector quantity because it involves magnitude only.
Physics
1 answer:
Llana [10]3 years ago
4 0
<span>It is a vector quantity because it involves magnitude and direction.</span>
You might be interested in
Explain why a chlorinated swimming pool water would be a homogenous mixture?
Ainat [17]
<span>The water and chlorine mix completely and do not separate or form layers, thus they form a homogenous mixture.</span>
3 0
3 years ago
A toboggan approaches a snowy hill moving at 12.4 m/s. The coefficients of static and kinetic friction between the snow and the
Harrizon [31]

Answer:

a) Acceleration while the toboggan is going uphill = 8.85 m/s²

b) Acceleration of the toboggan is going downhill = 4.76 m/s²

Explanation:

Resolving the normal reaction into vertical and horizontal component

Nₓ = mg sin θ

Nᵧ = mg cos θ

The frictional force on the toboggan = Fr = μmg cos θ (note that μ = μ(k) = the coefficient of kinetic friction)

Doing a Force balance on the x component taken in the axis parallel to the inclined plane.

The net force that has to accelerate the toboggan has to match the frictional force acting downwards of the plane (In the opposite direction to motion) and x-component of the Normal reaction

ma = Nₓ + Fr

ma = (mg sin θ) + (μmg cos θ)

a = g[(sin 44°) + (0.29 cos 44°)

a = 9.8(0.6947 + 0.2086) = 8.85 m/s²

b) While coming downhill,

The frictional force is acting uphill now (In the direction opposite to motion),

The force balance is

ma = (mg sin θ) - (μmg cos θ)

a = g[(sin 44°) - (0.29 cos 44°)]

a = 9.8(0.6947 - 0.2086)

a = 4.76 m/s²

3 0
3 years ago
At t = 0, a car registers at 30 miles/hr. Forty seconds later, the car’s velocity is now at 50 miles/hr. Assuming constant accel
ratelena [41]
D.

50 mph - 30 mph= 20 mph net velocity
change.
20mph/3600 seconds/hour= .00555 MPS
.0055 miles per second


40 seconds to complete the change
.0055/40= .000138

7 0
3 years ago
A tradesman sharpens a knife by pushing it with a constant force against the rim of a grindstone. The 30-cm-diameter stone is sp
Lorico [155]

Answer:

a. 0.21 rad/s2

b. 2.205 N

Explanation:

We convert from rpm to rad/s knowing that each revolution has 2π radians and each minute is 60 seconds

200 rpm = 200 * 2π / 60 = 21 rad/s

180 rpm = 180 * 2π / 60 = 18.85 rad/s

r = d/2 = 30cm / 2 = 15 cm = 0.15 m

a)So if the angular speed decreases steadily (at a constant rate) from 21 rad/s to 18.85 rad/s within 10s then the angular acceleration is

\alpha = \frac{\Delta \omega}{\Delta t} = \frac{21 - 18.85}{10} = 0.21 rad/s^2

b) Assume the grind stone is a solid disk, its moment of inertia is

I = mR^2/2

Where m = 28 kg is the disk mass and R = 0.15 m is the radius of the disk.

I = 28*0.15^2/2 = 0.315 kgm^2

So the friction torque is

T_f = I\alpha = 0.315*0.21 = 0.06615 Nm

The friction force is

F_f = T_f/R = 0.06615 / 0.15 = 0.441 N

Since the friction coefficient is 0.2, we can calculate the normal force that is used to press the knife against the stone

N = F_f/\mu = 0.441/0.2 = 2.205 N

7 0
3 years ago
Can anyone plzzzz answer this question... Cuz it's really urgent....
nlexa [21]

The fastest in speed of sound is steel. The slowest in speed of sound is oxygen. Hope this helped! I don't really know how to answer this but by looking at the table it looks like this can be one of the conclusions.

4 0
3 years ago
Read 2 more answers
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