Question

Exercise 1.9

100 N
400 mm
100 mm
300 N
Determine
1.
2. work output
3.
work input into the wheel barrow
Properties of Matter
mechanical advantage
0.2m
Figure 1.27: Lifting a load over steps
A man lifts a load of 300N on wheel barrow through a load distance of 100mm with
force 100N through effort distance of 400mm.
0.2m
0.2m
4. velocity ratio
5. efficiency of the machine
If the man took 5 minutes to push the wheel barrow with 80 N through a horizontal
distance 10 m. Determine his power.
If the man is required to move the load on the room three steps each 0.2m above,
which strategy should apply to accomplish the task. Explain your answer.

Answer 1

Step-by-step explanation:

1.) Work input = force on the machine x distance

300 x (100/1000)

= 30N.

2.Work output = Force on the machine x distance

=100 x (0.2+0.2+0.2)

=60N

3.) M.A = load/ effort

=300/(400/1000)

120N

4.) Velocity ratio = work out put/ work input

= 60/ 30

=2N

5.) Efficiency = M.A/ V.R x 100

= 120/2 x 100

= 6000%

6.) power = work done(force x distance) / Time

= 80 x10 / (5x60)

= 800 / 300

= 2.667J

Answer 2

Hello there, see below!

To solve this problem, let's calculate each parameter step by step:

Work Input:

Work input is the work done by the person on the wheelbarrow. It can be calculated using the formula:

Work Input = Force × Effort Distance

Work Input = 100 N × 0.4 m

Work Input = 40 Joules

Work Output:

Work output is the work done against the load. It can be calculated using the formula:

Work Output = Load × Load Distance

Work Output = 300 N × 0.1 m

Work Output = 30 Joules

Mechanical Advantage:

Mechanical advantage is the ratio of the load to the effort. It can be calculated using the formula:

Mechanical Advantage = Load / Effort

Mechanical Advantage = 300 N / 100 N

Mechanical Advantage = 3

Velocity Ratio:

Velocity ratio is the ratio of the distance moved by the effort to the distance moved by the load. It can be calculated using the formula:

Velocity Ratio = Load Distance / Effort Distance

Velocity Ratio = 0.1 m / 0.4 m

Velocity Ratio = 0.25

Efficiency:

Efficiency is the ratio of work output to work input, expressed as a percentage. It can be calculated using the formula:

Efficiency = (Work Output / Work Input) × 100

Efficiency = (30 J / 40 J) × 100

Efficiency = 75%

Now, let's address the second part of your question about moving the load up three steps each 0.2 m high. To accomplish this task efficiently, the person should use a mechanical advantage greater than or equal to the weight of the load divided by the effort required to lift it.

In this case, the weight of the load is 300 N, and if the person is applying a force of 100 N, the mechanical advantage should be at least 3 (300 N / 100 N) to lift the load efficiently. Since the mechanical advantage of the wheelbarrow is already 3, it can be used to move the load up the steps with the desired efficiency. The person can maintain the same force of 100 N while applying it over the effort distance of 400 mm (0.4 m) to overcome the load distance of 100 mm (0.1 m) per step. This will ensure that the load is lifted with the desired mechanical advantage and efficiency.