To find the work done in lifting the object, we can use the formula for gravitational potential energy, which is given by:
\[ W = m \cdot g \cdot h \]
where:
- \( W \) is the work done,
- \( m \) is the mass of the object (in kg),
- \( g \) is the acceleration due to gravity (approximately \( 9.81 , \text{m/s}^2 \)),
- \( h \) is the height (in m) the object is lifted.
For this problem:
- \( m = 4.5 , \text{kg} \)
- \( g = 9.81 , \text{m/s}^2 \)
- \( h = 0.9 , \text{m} \)
Now we can plug these values into the formula:
\[ W = 4.5 , \text{kg} \cdot 9.81 , \text{m/s}^2 \cdot 0.9 , \text{m} \]
Calculating this:
\[ W = 4.5 \cdot 9.81 \cdot 0.9 \]
\[ W \approx 39.63 , \text{J} \]
Rounding to two significant figures, we find:
\[ W \approx 40 , \text{J} \]
So the work done in lifting the object is approximately 40 J.
The correct answer from the options provided is:
40 J
1 answer