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3 years ago

What makes a submarine dive?

1 answer:

8 0

Letting water into its tanks, and letting it push air out, increases the density of the submarine. Once its density becomes greater than 1 (the density of the water it's floating in), it starts to sink.

The more water is let into the tanks, the greater the sub's density becomes, and the faster it sinks ... (it becomes more like a rock).

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It is at rest for 3 seconds before moving at constant speed for 10 seconds.

Anestetic [448]

Answer:

The answer is B.

Explanation:

You're given a position vs. time graph. The the slope of the line is the change in position over time - in other words, the speed.

A positive slope indicates a positive change in position over time and therefore a positive speed. The more positive the slope, the greater the change and the greater the positive speed.

A negative slope indicates a negative change in position over time and therefore a negative speed. The more negative the slop, the greater the change and the greater the negative speed.

A horizontal slope (i.e. slope of 0) indicates no change in position over time. In other words, the speed is 0 and the object is stationary.

With this in mind, you can see the object is initially moving with a positive speed for 3 s (from t=0 to t=3), then is at rest for 3 s (from t=3 to t=6), then is moving at a (higher) positive speed for 4 s (from t=6 to t=10). You can see then that the answer is B.

A is wrong because after being at rest the object moves at a constant speed for only 4 s.

C is wrong because by the time the object gets to 5cm, it has moved at 3 different speeds (first positive slope, horizontal slope, second positive slope).

D is wrong because the object moves from 0 to 3cm in 3 s - a speed of 3cm/3s = 1cm/s.

7 0

3 years ago

Which of the following is the most appropriate definition of organic compound?

Varvara68 [4.7K]

Answer:

D. a solid, liquid, or gaseous compound that is found in living organisms

Explanation:

7 0

3 years ago

Read 2 more answers

Object 1 has a mass of 7.0kg and a initial velocity of 17.0 m/s. Object 2 has a mass of 8.0kg and a initial velocity of -14.0 m/

Naily [24]

$\\ \sf\longmapsto m1v1+m2v2=(m1+m2)v3$

$\\ \sf\longmapsto 7(17)+8(-14)=(7+8)v3$

$\\ \sf\longmapsto 119-112=15v3$

$\\ \sf\longmapsto 15v3=7$

$\\ \sf\longmapsto v3=7/15$

$\\ \sf\longmapsto v3=2.1m/s$

4 0

2 years ago

1) Little Timmy wants to measure how tall his house is. He doesn’t have a tape measure but does have a stopwatch. He recruits Bi

kifflom [539]

1) 13.7 m

The motion of the rock is a free fall, with constant acceleration g=9.8 m/s^2 towards the ground, so the total distance it covers is given by the SUVAT equation:

$S=\frac{1}{2}gt^2$

where S is the height of the house, and t is the time the rock takes to reach the ground. Substituting t=1.67 s, we find:

$S=\frac{1}{2}(9.8 m/s^2)(1.67 s)^2=13.7 m$

2) 105.5 m

The motion of the stuffed chicken is a projectile motion, with a uniform horizontal motion (with constant velocity of v=36.0 m/s) and a vertical accelerated motion (with constant acceleration of g=9.8 m/s^2).

First of all, we can find the total time of the ball by considering the vertical motion only. We know the vertical distance covered, S=42.2 m, so the time of the fall is

$S=\frac{1}{2}gt^2\\t=\sqrt{\frac{2S}{g}}=\sqrt{\frac{2(42.2 m)}{9.8 m/s^2}}=2.93 s$

And now we can consider the horizontal motion to find the horizontal distance covered by the stuffed chicken:

$d=vt=(36.0 m/s)(2.93 s)=105.5 m$

3) 49.4 m

Again, the motion of the ball is a projectile motion, with a horizontal motion and a vertical motion.

The range of a projectile launched from the ground can be found by using the formula:

$d=\frac{v^2}{g} sin 2 \theta$

where, in this case:

v = 22.0 m/s is the initial velocity

$\theta=45^{\circ}$

Substituting into the formula, we find

$d=\frac{(22.0 m/s)^2}{9.8 m/s^2}(sin (2\cdot 45^{\circ}))=49.4 m$

4) 9.6 m/s^2

The frictional force acting on the monkey is given by:

$F_f = \mu mg=(0.16)(31.0 kg)(9.8 m/s^2)=48.6 N$

where $\mu$ is the coefficient of friction and m is the mass of the monkey.

We have two forces acting on the monkey: the push of F=345 N and the frictional force acting in the opposite direction. According to Newton's second law, the net force will be equal to the product between the monkey's mass and its acceleration, so we can find the acceleration:

$F-F_f=ma\\a=\frac{F-F_f}{m}=\frac{345 N-48.6 N}{31.0 kg}=9.6 m/s^2$

5) 462.3 N

The horizontal component of the pushing force is:

$F_x = F cos \theta = (648 N)(cos 25^{\circ})=587.3 N$

The frictional force, acting in the opposite direction, is

$F_f = \mu mg=(0.17)(75.0 kg)(9.8 m/s^2)=125.0 N$

where $\mu$ is the coefficient of friction and m is the mass of the box.

The net force on the box is therefore given by the net force on the horizontal direction:

$F_{net}=F_x -F_f=587.3 N -125.0 N=462.3 N$

6) 89.5 N

First of all we need to calculate the total weight of the table and the items above it.

The weight of the table is:

$W=mg=(25.0 kg)(9.8 m/s^2)=245 N$

So the total weight of the table and the items is

$W=245 N+63 N+12 N+44 N+24 N+9N+10N=407 N$

The force needed to get the table moving must be at least equal to the frictional force, which is equal to the product between the coefficient of friction and the weight of the all stuff:

$F=F_f = \mu W=(0.22)(407 N)=89.5 N$