A baseball bat hits a ball is an example of contact force.
Option A.
<h3><u>Explanation:</u></h3>
Contact force is defined as those forces which are acting between two bodies by actually touch between two bodies.
In case of the book falling to ground, the force acting is the gravitational force. Gravitational force acts even when two bodies aren't in contact. So its a non contact force.
Similar is the condition of the leaf and ground where the gravitational force acts.
The magnetic force between the paper clip and the magnet is also non contact force, which acts even when two bodies aren't in contact.
But the bat hitting the ball is having direct contact between the two bodies, and their contact is what makes the ball fly off. So its a contact force.
Answer:
Geology is the study of the Earth that involves the process at Earth, materials of which it is made, and its history.
<u>Geologists combine both laboratory and field data to illustrate the results of their research. Some observations that can the geologist make by working outdoors instead of in a lab are as follows:</u>
- Understanding and exploring the earth's surface closely using geophysical tools.
- Collecting samples by own and make some interpretations at the same time.
- Observation of the landscapes
- Close observation of outcrops
Answer:
The maximum safe depth in salt water is 3758.2 m.
Explanation:
Given that,
Diameter = 20 cm
Radius = 10 cm
Thickness = 9.0 cm
Force 
Inside pressure = 1.0 atm
We need to calculate the area
Using formula of area
Put the value into the formula
We need to calculate the pressure
Using formula of pressure
Put the value into the formula
We need to calculate the maximum depth
Using equation of pressure
Put the value into the formula
Hence, The maximum safe depth in salt water is 3758.2 m.
Answer:
F= 5.71 N
Explanation:
width of door= 0.91 m
door closer torque on door= 5.2 Nm
In order to hold the door in open position we need to exert an equal and opposite torque, to the door closer torque, on the door.
so wee need to exert 5.2 Nm torque on the door.
If we want to apply minimum force to exert the required torque we need to apply force perpendicularly on the door knob (end of door) so that to to greater moment arm.
T= r x F
T= r F sin∅
F= T/ (r * sin∅)
F= 5.2/ (0.91 * 1)
F= 5.71 N
