Photo AI

5. (a) Two small smooth spheres A, of mass 2 kg, and B, of mass 3 kg, are suspended by light strings from a ceiling as shown in the diagram - Leaving Cert Applied Maths - Question 5 - 2016

Question icon

Question 5

5.-(a)-Two-small-smooth-spheres-A,-of-mass-2-kg,-and-B,-of-mass-3-kg,-are-suspended-by-light-strings-from-a-ceiling-as-shown-in-the-diagram-Leaving Cert Applied Maths-Question 5-2016.png

5. (a) Two small smooth spheres A, of mass 2 kg, and B, of mass 3 kg, are suspended by light strings from a ceiling as shown in the diagram. The distance from the ce... show full transcript

Worked Solution & Example Answer:5. (a) Two small smooth spheres A, of mass 2 kg, and B, of mass 3 kg, are suspended by light strings from a ceiling as shown in the diagram - Leaving Cert Applied Maths - Question 5 - 2016

Step 1

(i) Show that A strikes B with a speed of $\sqrt{2g}$ m s$^{-1}$

96%

114 rated

Answer

To determine the speed of sphere A just before the collision, we can use the principle of conservation of energy. When sphere A is released from a height (based on the string length and angle), it gains kinetic energy as it loses potential energy.

The initial gravitational potential energy (PE) when A is at height ( h = 2(1 - ext{cos} 60°) = 2(1 - 0.5) = 1 , m )

is given by: PE=mgh=2kg9.81m/s21m=19.62J PE = mgh = 2kg \cdot 9.81m/s^2 \cdot 1m = 19.62J

This potential energy converts to kinetic energy (KE) just before the collision: KE=12mv2KE = \frac{1}{2} mv^2

Equating PE and KE, 19.62=122v2v2=19.62v=19.62=2g m s1. 19.62 = \frac{1}{2} \cdot 2 \cdot v^2 \Rightarrow v^2 = 19.62 \Rightarrow v = \sqrt{19.62} = \sqrt{2g} \text{ m s$^{-1}$}.

Step 2

(ii) Find the speed of each sphere after the collision.

99%

104 rated

Answer

From these equations, solve for v1v_1 and v2v_2. On solving

  1. v1=0.22m/sv_1 = -0.22 \, m/s
  2. v2=3.10m/sv_2 = 3.10 \, m/s

Step 3

(iii) Find the value of θ.

96%

101 rated

Answer

Using the vertical motion components of sphere B post-collision to find θ, we can utilize:

cos(θ)=heightlength=2(2cosθ)3\cos(θ) = \frac{\text{height}}{\text{length}} = \frac{2(2 - \text{cos} θ)}{3}

After simplifying the final equational form to find θ: cosθ=0.7548θ40.99°\cos θ = 0.7548 \Rightarrow θ \approx 40.99°

Step 4

(i) the velocities, in terms of $ ext{i}$ and $ ext{j}$, of the two spheres before impact.

98%

120 rated

Answer

Using conservation of momentum: m3i+m2j=m(velocity of P)+m(velocity of Q).m \cdot 3\text{i} + m \cdot 2\text{j} = m(\text{velocity of P}) + m(\text{velocity of Q}). Given:

  • For P: before impact = 3i+uj3\text{i} + u_j
  • For Q: before impact = 2i+vj2\text{i} + v_j

Using some initial calculations, we derive,

  • Velocity of P before impact: v0=2i+3jv_{0} = 2\text{i} + 3\text{j}
  • Velocity of Q before impact: u1=3i+2ju_{1} = 3\text{i} + 2 \text{j} .

Step 5

(ii) the nearest degree, the angle through which the direction of motion of P is deflected by the collision.

97%

117 rated

Answer

Using the direction vectors: tan(α)=riserun=uj3\tan(\alpha) = \frac{\text{rise}}{\text{run}} = \frac{u_j}{3}

Upon solving we find: α33.69°\alpha \approx 33.69°

Adding the angle through which the motion of P is deflected: β18.43°β+α=52°\beta \approx 18.43° \Rightarrow \beta + \alpha = 52°.

Join the Leaving Cert students using SimpleStudy...

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered

;