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3 years ago

Does anyone know how to do this? i tried doing some but i don't think i did them right.

Physics

1 answer:

geniusboy [140]3 years ago

6 0

When the velocity of an object is constant, there is no acceleration . Acceleration is defined as a change in velocity over time.
Problem three wants to know if velocity and acceleration have the same signs. I'll assume that on the x-axis the kick goes to the right, that means that velocity has a positive direction therefore positive, acceleration however, is slowing down therefore negative, this is commonly mistaken as deceleration but it's just negative acceleration.
4. when there's constant acceleration, velocity is changing all the time
(constant acceleration would be seen as a parabolic motion where velocity is seen changing at every point.)
you can use the four kinematic equations to find several things like time, distance, and acceleration for the rest

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A seesaw pivots as shown in below. What is the net torque about the pivot point?

rodikova [14]

Answer:

2.3 Nm clockwise

Explanation:

Take counterclockwise to be positive and clockwise to be negative.

∑τ = (3 N) (2.5 m) − (7 N) (1.4 m)

∑τ = 7.5 Nm − 9.8 Nm

∑τ = -2.3 Nm

The net torque is 2.3 Nm clockwise.

7 0

4 years ago

To cross the river a swimmer chooses the direction minimizing the amount of time spent in the water. The swimmer swims at a cons

Lynna [10]

Answer:

304 meters downstream

Explanation:

The given parameters are;

The speed of the swimmer = 2.00 m/s

The width of the river = 73.0 m

The speed of the river = 8.00 m/s

Therefore;

The direction of the swimmer's resultant velocity = tan⁻¹(8/2) ≈ 75.96° downstream

The distance downstream the swimmer will reach the opposite shore = 4 × 73 = 304 m downstream

The distance downstream the swimmer will reach the opposite shore = 304 m downstream

6 0

3 years ago

A river flows with a speed of 0.600 m/s. A student first swims upriver 0.500 km, then turns around and returns to his starting p

DerKrebs [107]

Answer:

a) 1111.0 seconds

b) 833.3 s

c) Because of proportions

Explanation:

a) Total time of round trip is the sum of time upriver and time downriver

$t_{total}=t_{up}+t_{down}$

Time upriver is calculated with the net speed of student and 0.500 km:

$t_{up}=\frac{d_{istance}}{|v_{swimmer}|} ;\\v_{swimmer}=v_{relative to river}+v_{river}=-1.2+0.6=-0.6 m/s\\t_{up}=\frac{500 m}{0.6 m/s}=833.3 s$

(Becareful with units 0.5 km= 500m) Similarly of downriver:

$t_{down}=\frac{d_{istance}}{|v_{swimmer}|} ;\\v_{swimmer}=1.2+0.6=1.8 m/s\\t_{down}=\frac{500 m}{1.8 m/s}=277.7 s$

So the sum is:

$t_{total}=1111.0s$

b) Still water does not affect student speed, so total time would be simply:

$t_{total}=\frac{1000 m}{1.2 m/s}=833.3 s$

c) For the upriver trip, student moved half the distance in half speed of the calculation in b), so it kept the same ratio and therefore, same time. So the aditional time is actually the downriver.

6 0

3 years ago

Students run an experiment to determine the rotational inertia of a large spherically shaped object around its center. Through e

Alex73 [517]

Answer: I = 3.6 m3

(C)

Explanation:

moment of inertia for spherically shaped object around it's center is given as

I = (2/5) mr²

substituting the r = 3m²

I = (2/5)*(9) m3

I = 3.6 m3

5 0

4 years ago

After release of jet, energy is lost by the engine. How principle of conservation of energy is obeyed in this condition.

HACTEHA [7]

Answer:

The principle of conservation of energy states that in a closed system, the energy can neither be created nor destroyed between interacting particles and remains constant or transformed from one form to another

In the jet engine, the release of jet changes the number of interacting particles in the engine, and given that energy cannot be created in the instantaneously closed system of the engine, energy is carried away and therefore lost by particles in the jet exhaust

The conservation of energy principle is therefore obeyed in the condition in which the jet engine losses energy by the release of jet

Explanation:

5 0

3 years ago