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DerKrebs [107]
3 years ago
8

Very lost please help.

Physics
1 answer:
V125BC [204]3 years ago
6 0
A) The acceleration is due to gravity at any given point if you look at it vertically, so -10 m/s^2.

b) sin(25) = V_y/V, so V_y = V*sin(25). We use V = V_0 + a t and then the final speed must be 0 because it stops at the highest point. So 0 = V_y - 10t. Solve for t and you get t = 32sin(25)/10 = 16sin(25)/5

c) Y = Y_0 + V_0t + (1/2)at^2, and then we plug the values: Y_m_a_x = 32sin(25)*t - (1/2)*10*t^2 and we already have the time from "b)", so Y_m_a_x = [(32sin(25))*(32sin(25)/10)] - 5(32sin(25)/10)^2; then we just rearrange it Y_m_a_x = 10[(32sin(25))^2/100] - 5 [(32sin(25))^2/100] and finally Y_m_a_x = 5[(32sin(25))^2/100] = (32sin(25))^2/20
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Need some help
Keith_Richards [23]

The answer is C) the density of the rock

Density of rock is the dependent variable, because it depends on the temperature. The temperature can’t be the dependent variable because ,the density of a rock does not have magical powers that can change temperature of a room. However changing the temperature of the room ,will change the density of the rock. Hope this helps !

4 0
3 years ago
Which of the following describes the least amount of work being done? A. wind turning a windmill B. a batter hitting a baseball
Mandarinka [93]

Answer:

a ball hanging from a tall pole

Explanation:

work is force times a distance in the direction of the force. The ball just hanging there has no motion, so is associated with no work. Work was probably done in the hanging process, but none after.

6 0
3 years ago
Read 2 more answers
Tarzan is in the path of a pack of stampeding elephants when Jane swings in to the rescue on a rope vine, hauling him off to saf
timurjin [86]

Answer:

h = 3.56 m

Explanation:

  • Assuming no friction on the rope or air resistance, we can apply the conservation of mechanical energy principle to the first part of the trajectory, from when Jane starts her swing till she catches Tarzan at the ground level.

⇒      \Delta K + \Delta U = 0 (1)

  • Rearranging terms, we get:

        U_{ij} + K_{ij} = U_{fj} + K_{f}   (2)

  • Now, as Jane starts from rest, Kij =0.
  • if we choose the ground level as our zero reference level, it will be also  Ufj = 0.
  • Replacing in (2) by the expressions of Uij and Kfj, we have:

        m_{j} * g* h_{ij} = \frac{1}{2} * m_{j} * v_{fj} ^{2}  (3)

  • Replacing in (3) by the givens, and rearranging terms, we can solve for vfj, as follows:

       v_{fj} =\sqrt{2*9.8 m/s2*27 m} = 23 m/s (4)

  • Now, as once jane catches Tarzan, both continue swinging together, we can take the catching moment as a completely inelastic collision.
  • Assuming no external forces act during the collision, total momentum must be conserved.

⇒     p_{o} = p_{f}    (5)

  • Assuming that Tarzan is at rest when Jane catches him, the initial momentum will be simply as follows:

        p_{o} = m_{j} * v_{j} = 49 kg * 23 m/s = 1127 kg*m/s (6)

  • The final momentum, will be just the product of the combined mass of Jane and Tarzan times the common speed for them after the collision:

        p_{f} = (m_{j} + m_{t} ) * v_{jt} = 135 kg*  v_{jt}  (7)

  • As (6) and (7) are equal each other, we can solve for vjt, as follows:

       v_{jt} = \frac{1127 kg*m/s}{135 kg} = 8.35 m/s (8)

  • Finally we can apply the same energy conservation principle to the last part of the trajectory, as follows:

       U_{ijt} + K_{ijt} = U_{fjt} + K_{fjt}   (9)

  • We know that Uijt = 0 and also that Kfjt = 0, due to both starts from the ground level and reach to the highest point before starting to fall down, so at this point, the kinetic energy will be zero.
  • Replacing by the givens and the result from (8), we can solve for the h as follows:
  • h_{f} =\frac{v_{ijt} ^{2} }{2*g} = \frac{69.7m2/s2}{2*9.8m/s2} = 3.56 m
8 0
3 years ago
I need help ASAP doing a test rn
Irina-Kira [14]

Answer:

Thinking also friction force

Explanation:

7 0
3 years ago
Read 2 more answers
A ball dropped from a bridge takes three seconds to reach the water below how far is the bridge above the water?
tatuchka [14]

<u>Given that:</u>

Ball dropped from a bridge at the rate of 3 seconds

Determine the height of fall (S) = ?

      As we know that, S = ut + 1/2 ×a.t²

                          u =initial velocity = 0

                          a= g =9.81 m/s  (since free fall)

                            S = 0+ 1/2 × 9.81 × 3²

                          <em> S = 44.145 m</em>

<em>44.145 m far is the bridge from water</em>

6 0
3 years ago
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