An object is lifted vertically 3 m against gravity. If the mass of the object is
Practice Questions
Q1
An object is lifted vertically 3 m against gravity. If the mass of the object is 4 kg, what is the work done against gravity? (g = 9.8 m/s²)
117.6 J
39.2 J
29.4 J
19.6 J
Questions & Step-by-Step Solutions
An object is lifted vertically 3 m against gravity. If the mass of the object is 4 kg, what is the work done against gravity? (g = 9.8 m/s²)
Correct Answer: 117.6 J
Step 1: Identify the mass of the object. The mass is given as 4 kg.
Step 2: Identify the height the object is lifted. The height is given as 3 m.
Step 3: Identify the acceleration due to gravity. It is given as 9.8 m/s².
Step 4: Use the formula for work done against gravity, which is Work = mass × gravity × height.
Step 5: Substitute the values into the formula: Work = 4 kg × 9.8 m/s² × 3 m.
Step 6: Calculate the multiplication: 4 × 9.8 = 39.2, then 39.2 × 3 = 117.6.
Step 7: The final answer for the work done against gravity is 117.6 Joules.
Work Done Against Gravity – The work done against gravity is calculated using the formula W = mgh, where W is work, m is mass, g is the acceleration due to gravity, and h is the height lifted.
Units of Measurement – Understanding the units involved (kilograms for mass, meters for height, and Newtons for force) is crucial for correctly calculating work in joules.
