A solved problem on Mechanics
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A laundry basket is pulled along a frictionless surface with a force of 6N for 8 seconds. Given that the basket's initial velocity was 0 ms-1 and final velocity was 2.4 ms-1, the acceleration of the basket is calculated to be 0.3 ms-2. Using the equation F=ma, where F is 6N, a is 0.3 ms-2, the mass of the basket is calculated to be 20 kg.
A solved problem on Mechanics
- 1. Mechanics Question A laundry basket, which is initially at rest on a horizontal surface, is pulled along the surface with a horizontal force of magnitude 6N for 8 seconds. At the end of the period the speed of the basket is 2.4 ms-1. Assuming that the surface may be modelled as frictionless, find the mass of the basket. Answer Since the laundry basket is initially at rest, therefore its initial velocity (u) = 0 ms-1. The horizontal force (F) with which it is being pulled = 6 N. The time (t) through which it is being pulled = 8 seconds. The final velocity (v) of the basket = 2.4 ms-1.
- 2. Since a force is being applied, it is producing an acceleration in the motion of the basket. Let the acceleration produced be = ‘a’ ms-2. And the force F = ma , where ‘m’ is the mass of the basket. We know the value of ‘F’, so if we know that value of ‘a’, we can get the mass of the basket. In order to find ‘a’, we use the equation, v = u + at => 2.4 ms-1 = 0 ms-1 + (a ms-2) ⨯ 8 seconds
- 3. Therefore, acceleration ‘a’ = 0.3 ms-2. F = ma => 6 N = m ⨯ 0.3 ms-2 => m = 20 kg Therefore, the mass of the laundry basket is 20 kg. (Ans.)