Question

1. the work done in lifting 25 kg of bricks to a height of 20 m is (assume g = 9.8 m/s²)

(a) 250 j
(b) 600 j
(c) 2940 j
(d) 5880 j
(e) none of the above

Explanation:

Step1: Recall work - formula

The work done \(W\) in lifting an object is given by \(W = mgh\), where \(m\) is the mass, \(g\) is the acceleration due to gravity and \(h\) is the height.

Step2: Substitute values

Given \(m = 25\space kg\), \(g=9.8\space m/s^{2}\) and \(h = 20\space m\). Then \(W=25\times9.8\times20\).
First, \(25\times20 = 500\). Then \(500\times9.8=4900\space J\). Since \(4900\space J\) is not in the given options.

Answer:

(e) none of the above