Answer:
1. Muscular force
2. Speed decreases
3. higher than
4. decreases
5. air pressure
6. Inversely proportional to the area of contact
7. 20 N
8. 400 N / m2
9. 150 N
10. friction
Explanation:
1. During pushing the pushcart the person is required to use strength of his arms and legs muscles that will creat a force between the surfaces, hence the force used is muscular force.
2. The speed of car decreases while applying brakes because a friction is generated between the brakes and the wheel that reduces the kinetic energy of vehicle and decreases the speed of the vehicle.
3. The pressure of the water at the bottom of the pond is higher than at the surface of pond because water pressure increases with the depth of the water. Water pressure increases in the depth because weight of water over the body icreases as going deep.
4. At higher altitude the atomspheric pressure decreases because as the height in atmosphere increases the amount of air molecules decreases and so, less oxygen for breathing.
5. Air pressure allows the dropper to fill inks as dropper exerts a force on a surface of ink and due to the low pressure inside the dropper sucks up the liquid.
6. Pressure is defined as the perpendicular force exerted at the surface or it means force per unit area. Pressure is directly proportional to the force and inversely proportional to area of contact.
7. The boys exerts pressure in opposite direction on an object, hence the resultant force will be
resultant force = force 1 - force 2 = 60N−40N=20N.
8. pressure (P) is equal to force (F) per unit area (A)
P = F / A
= 800 / 2
= 400 N / m2
9. Pressure (P) = 300 Pa
Area of Cross-section (A) = 0.5 m²
Force = P × A
= 300 × 0.5
= 150 N
10. Friction is the force that is always applied against or opposite to the moving direction of an object. Friction is responsible to stop the movement of any moving object such as vehicles and sliding objects.
Hence, the correct option of the questions are:
1. Muscular force
2. Speed decreases
3. higher than
4. decreases
5. air pressure
6. Inversely proportional to the area of contact
7. 20 N
8. 400 N / m2
9. 150 N
10. friction
