Answer :
Final answer:
The work done in lifting a 1.2-kg book to 0.5 m high is 5.88 Joules. For lifting a 19-lb weight 8 ft high, which is equivalent to 8.62 kg and 2.4384 m, the work done is 206.62 Joules.
Explanation:
Work Done in Lifting Objects
The concept of work in physics is crucial for understanding energy transfer. When lifting an object against gravity, work is done on the object, and this can be calculated using the formula W = Fd, where W is work, F is the force applied, and d is the distance over which the force is applied.
Calculating Work for the Book and Weight
For part (a), the work done in lifting a 1.2-kg book to a height of 0.5 m is calculated using the force of gravity on the book (F = mg) and the height it is lifted (d). Therefore, the work done is W = (1.2 kg)(9.8 m/s2)(0.5 m) = 5.88 Joules.
For part (b), first, we convert the weight from pounds to kilograms (1 lb = 0.453592 kg) and feet to meters (1 ft = 0.3048 m). Thus, a 19-lb weight is equivalent to approximately 8.62 kg, and lifting it 8 ft off the ground converts to 2.4384 m. Hence, the work done is W = (8.62 kg)(9.8 m/s2)(2.4384 m) = 206.62 Joules.
Answer:
a) 5.88Nm b) 206.30Nm
Explanation:
Work is said to be done when a force applied to an object causes the object to change its position.
Mathematically, work done = Force × Distance
Given distance = height = 0.5m
Force = weight of the object = mass × acceleration due to gravity
Weight= 1.2×9.8
Weight = 11.76N
Work done = 11.76 × 0.5
Work done = 5.88Nm
b) Using similar formula as in question a;
Work done = Force × Distance
Given weight = 19lb
Since 1lb = 4.45N
19lb weight = 19×4.45 = 84.55N
Distance of object from the ground = 8ft
Since 1ft = 0.305m
8ft = 0.305×8 = 2.44m
Work done = 84.55×2.44
Work done = 206.30Nm
