Muscle power

The idea

The force resulting from the action of muscles, which contract and elongate when we walk, run, lift, push, jump or stretch, is called muscular force; it is a contact force.

Everything you do

You walk, run, lift a bag, push a door, jump and stretch.

What is behind all these actions?

• The action of muscles
• The action of magnets
• Nothing at all

Muscles or not

Tap the bin where each case belongs.

Muscles pull and relax

When we do any physical activity, muscles contract and elongate. The force that results from the action of muscles is muscular force. It is a contact force.

The force resulting from the action of muscles is called muscular force. Muscles contract and elongate when we walk, run, lift, push, jump or stretch. It is a contact force.

Notes

The force resulting from the action of muscles, which contract and elongate, is muscular force. It is a contact force.

Check yourself

The force resulting from the action of muscles is called …

Muscular force occurs when muscles …

Which of these uses muscular force?

Muscular force is a …

• muscular force — correct. Yes!
• magnetic force. Magnetic force comes from magnets.
• electrostatic force. Electrostatic force comes from charged objects.
• turn into magnets. Muscles do not turn into magnets. They contract and elongate.
• contract and elongate — correct. Yes!
• stop working. Muscular force comes from muscles working.
• A ball falling down. That is the Earth's pull, not muscles.
• A magnet attracting a clip. That is magnetic force, not muscles.
• Lifting a bag — correct. Yes!
• contact force — correct. Yes!
• non-contact force. Muscular force needs contact, directly or indirectly.
• force that never needs any object. A force needs two objects. Muscular force is a contact force.