/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 84 Two blocks \(\left(m_{1}=1.23 \m... [FREE SOLUTION] | 91Ó°ÊÓ

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Two blocks \(\left(m_{1}=1.23 \mathrm{~kg}\right.\) and \(m_{2}=2.46 \mathrm{~kg}\) ) are glued together and are moving downward on an inclined plane having an angle of \(40.0^{\circ}\) with respect to the horizontal. Both blocks are lying flat on the surface of the inclined plane. The coefficients of kinetic friction are 0.23 for \(m_{1}\) and 0.35 for \(m_{2}\). What is the acceleration of the blocks?

Short Answer

Expert verified
**Answer:** The acceleration of the blocks is 3.97 m/s² downwards on the inclined plane.

Step by step solution

01

Calculate the gravitational force acting on each block

The gravitational force acting on each block can be calculated using the formula \(F_g = mg\), where \(m\) is the mass of the block and \(g\) is the acceleration due to gravity (approximately \(9.81\,\mathrm{m/s^2}\)). For block 1, \(F_{g1} = m_1g = 1.23\,\mathrm{kg} \times 9.81\,\mathrm{m/s^2} = 12.08\,\mathrm{N}\). For block 2, \(F_{g2} = m_2g = 2.46\,\mathrm{kg} \times 9.81\,\mathrm{m/s^2} = 24.15\,\mathrm{N}\).
02

Calculate parallel and perpendicular force components to the inclined plane

We will divide these gravitational forces into two components - one parallel to the inclined plane (\(F_{g \parallel}\)) and one perpendicular to the inclined plane (\(F_{g \perp}\)). We can do this using the angle of inclination and basic trigonometry. Parallel component: \(F_{g \parallel} = F_g \sin \theta\) Perpendicular component: \(F_{g \perp} = F_g \cos \theta\) For block 1: \(F_{g1 \parallel} = 12.08\,\mathrm{N} \times \sin(40^{\circ}) = 7.76\,\mathrm{N}\) \(F_{g1 \perp} = 12.08\,\mathrm{N} \times \cos(40^{\circ}) = 9.26\,\mathrm{N}\) For block 2: \(F_{g2 \parallel} = 24.15\,\mathrm{N} \times \sin(40^{\circ}) = 15.5\,\mathrm{N}\) \(F_{g2 \perp} = 24.15\,\mathrm{N} \times \cos(40^{\circ}) = 18.5\,\mathrm{N}\)
03

Calculate the frictional force

The frictional force can be calculated using the formula \(F_f = \mu F_{g \perp}\), where \(\mu\) is the coefficient of kinetic friction. For block 1, \(F_{f1} = \mu_1 F_{g1 \perp} = 0.23 \times 9.26\,\mathrm{N} = 2.13\,\mathrm{N}\) For block 2, \(F_{f2} = \mu_2 F_{g2 \perp} = 0.35 \times 18.5\,\mathrm{N} = 6.48\,\mathrm{N}\)
04

Calculate the net force acting on the system

To find the net force acting on the system, we subtract the frictional forces from the parallel gravitational forces for both blocks: \(F_{net} = (F_{g1 \parallel} - F_{f1}) + (F_{g2 \parallel} - F_{f2}) = (7.76 - 2.13)\,\mathrm{N} + (15.5 - 6.48)\,\mathrm{N} = 14.65\,\mathrm{N}\)
05

Use Newton's second law to calculate the acceleration

According to Newton's second law, \(F = ma\). Since we have the net force acting on the system (\(F_{net}\)) and the total mass of the system (\(m_{total} = m_1 + m_2\)), we can calculate the acceleration of the blocks: \(14.65\,\mathrm{N} = (1.23\,\mathrm{kg} + 2.46\,\mathrm{kg}) \times a\) Solving for \(a\): \(a = \frac{14.65\,\mathrm{N}}{(1.23+2.46)\,\mathrm{kg}} = \frac{14.65}{3.69}\,\mathrm{m/s^2} = 3.97\,\mathrm{m/s^2}\) The acceleration of the blocks is \(3.97\,\mathrm{m/s^2}\) downwards on the inclined plane.

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