1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Jlenok [28]
3 years ago
12

9) At a construction site, a small crane is raising two boxes of nails on a plank to the roof. One box has already been opened a

nd is half full, while the other box is new. The boxes, including the nails, weight 10 kg and 20 kg, respectively, and are the same size
a) As the plank tilts towards the heavier box, predict which box of nails will start to slide first. Explain your prediction
Physics
2 answers:
Varvara68 [4.7K]3 years ago
8 0

Answer:

The two boxes will start sliding at the same angle. Their different masses does not affect when one of the boxes will start sliding.

Explanation:

The two boxes will start sliding when the frictional force,Ff= The gravitational force,Fg

Ff= mgcos theta× coefficient of friction

Fg= mgsintheta

Ff=Fg= mgsintheta=mgcos theta×coefficient of friction

Dividing through with mg on both sides gives

Sintheta=ucostheta

Sintheta/costheta= Tan theta

Theta= tan^-1(coefficient of fricition)

From the solution mass of the boxes and gravity does not affect when the boxes will start sliding.

rosijanka [135]3 years ago
3 0
Box 1 (having a mass of 10 kg) will slide first as it has less inertia than the other box. It will also require less force to overcome static friction between the surface of the plank and that of the first box.
You might be interested in
A 5.00-a current runs through a 12-gauge copper wire (diameter 2.05 mm) and through a light bulb. copper has 8.5 * 1028 free ele
vlada-n [284]

The correct answer is: 3.125*10^{19} electrons/second

Explanation:

5A current is passing through the copper wire and the light bulb; it means that 5 Coulombs of charge per second is passing through the wire (as current = coulombs/second). To find the electrons per second, the following formula is used:

Electrons per second = n_e=\frac{5}{e}=\frac{5}{ 1.60\cdot 10^{-19}}=3.125*10^{19}

7 0
3 years ago
Read 2 more answers
A ski jumper starts at the top of a 400m high hill before skiing down to the bottom. If the ski jumper has a mass of 75kg how mu
alekssr [168]

Answer:B. 30,000 J

Explanation:

6 0
2 years ago
A 1.8-kg object is attached to a spring and placed on frictionless, horizontal surface. A force of 40 N stretches a spring 20 cm
Sergio [31]

Answer:

a) k = 200 N/m

b) E = 4 J

c) Δx = 6.3 cm

Explanation:

a)

  • In order to find force constant of the spring, k, we can use the the Hooke's Law, which reads as follows:

       F = - k * \Delta x (1)

  • where F = 40 N and Δx =- 0.2 m (since the force opposes to the displacement from the equilibrium position, we say that it's a restoring force).
  • Solving for k:

       k =- \frac{F}{\Delta x} =-\frac{40 N}{-0.2m} = 200 N/m (2)

b)

  • Assuming no friction present, total mechanical energy mus keep constant.
  • When the spring is stretched, all the energy is elastic potential, and can be expressed as follows:

        U = \frac{1}{2}* k* (\Delta x)^{2} (3)

  • Replacing k and Δx by their values, we get:

       U = \frac{1}{2}* k* (\Delta x)^{2} = \frac{1}{2}* 200 N/m* (0.2m)^{2} = 4 J (4)

c)

  • When the object is oscillating, at any time, its energy will be part elastic potential, and part kinetic energy.
  • We know that due to the conservation of energy, this sum will be equal to the total energy that we found in b).
  • So, we can write the following expression:

        \frac{1}{2}* k* \Delta x_{1} ^{2} + \frac{1}{2} * m* v^{2}  = \frac{1}{2}*k*\Delta x^{2}   (5)

  • Replacing the right side of (5) with (4), k, m, and v by the givens, and simplifying, we can solve for Δx₁, as follows:

        \frac{1}{2}* 200N/m* \Delta x_{1} ^{2} + \frac{1}{2} * 1.8kg* (-2.0m/s)^{2}  = 4J   (6)

⇒      \frac{1}{2}* 200N/m* \Delta x_{1} ^{2}   = 4J  - 3.6 J = 0.4 J (7)

⇒     \Delta x_{1}   = \sqrt{\frac{0.8J}{200N/m} } = 6.3 cm (8)

6 0
2 years ago
A 72.8-kg swimmer is standing on a stationary 265-kg floating raft. The swimmer then runs off the raft horizontally with a veloc
nalin [4]

Answer:

-1.43 m/s relative to the shore

Explanation:

Total momentum must be conserved before and after the run. Since they were both stationary before, their total speed, and momentum, is 0, so is the total momentum after the run off:

m_sv_s + m_rv_r = 0

where m_s = 72.8, m_r = 265 are the mass of the swimmer and raft, respectively. v_s = 5.21 m/s, v_r are the velocities of the swimmer and the raft after the run, respectively. We can solve for v_r

265v_r + 72.8*5.21 = 0

v_b = -72.8*5.21/265 = -1.43 m/s

So the recoil velocity that the raft would have is -1.43 m/s after the swimmer runs off, relative to the shore

7 0
2 years ago
When the Earth is closest to the Sun, it is at:
ahrayia [7]

a). Perihelion . . . the point in Earth's orbit that's closest to the Sun.
                            We pass it every year early in January. 


b). Aphelion . . . the point in Earth's orbit that's farthest from the Sun.
                          We pass it every year early in July. 

c). Proxihelion . . . a made-up, meaningless word

d). Equinox . . . the points on the map of the stars where the Sun
                         appears to be on March 21 and September 21.

5 0
3 years ago
Other questions:
  • What produces light and all other electromagnetic waves?
    10·1 answer
  • Potential difference is measured in which units?<br> volts<br> amps<br> currents<br> watts
    9·2 answers
  • What are the three layers of the sun's atmosphere, in order of increasing distance from the surface?
    14·1 answer
  • A rock weighs 30 n on earth and another rock weighs 30 n on the moon. which rock has the greater mass?
    15·1 answer
  • A resistor and an ideal inductor are connected in series to an ideal battery having a constant terminal voltage V 0. (a) At the
    13·1 answer
  • You and I see, hear, and think with ___________________________. Waves carry _____________________. The wave in the speaker, on
    6·1 answer
  • A dairy farmer notices that a circular water trough near the barn has become rusty and now has a hole near the base. The hole is
    12·1 answer
  • Three equal 1.60-μCμC point charges are placed at the corners of an equilateral triangle with sides 0.800 mm long. What is the p
    11·1 answer
  • A baseball (A, weight 0.33 lb) moves horizontally at 20 ft/s when it strikes a stationary block (B, weight 10 lb), supported by
    12·1 answer
  • Does warm water hold more salt then cold water?
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!