Answer:
0.001 s
Explanation:
The force applied on an object is equal to the rate of change of momentum of the object:

where
F is the force applied
is the change in momentum
is the time interval
The change in momentum can be written as

where
m is the mass
v is the final velocity
u is the initial velocity
So the original equation can be written as

In this problem:
m = 5 kg is the mass of the fist
u = 9 m/s is the initial velocity
v = 0 is the final velocity
F = -45,000 N is the force applied (negative because its direction is opposite to the motion)
Therefore, we can re-arrange the equation to solve for the time:

Answer:
60 cm
Explanation:
We are given;
- Focal length of a concave mirror as 30.0 cm
- Object distance is 15.0 cm
We are required to determine the radius of curvature.
We need to know that the radius of a curvature is the radius of a circle from which the curved mirror is part.
We also need to know that the radius of curvature is twice the focal length of a curved mirror.
Therefore;
Radius of curvature = 2 × Focal length
Therefore;
Radius of curvature = 2 × 30 cm
= 60 cm
The total work done on the car is 784Joule.
<h3>What's the acceleration of the car?</h3>
- As per Newton's equation of motion, V= U+at
- U= initial velocity= 0 m/s
V= vinal velocity= 20m/s
t= time = 10s
a= acceleration
=> a= 20/10= 2m/s²
<h3>What's the distance covered by the car in 10 seconds?</h3>
- As per Newton's equation of motion,
V²-U² = 2aS
- S= distance covered by the car
- So, 20²-0=2×2×S=4S
=> 400= 4S
=> S= 400/4= 100m
<h3>What's the work done on the car due to frictional force?</h3>
Work done by frictional force= frictional force × distance
= (0.2×4×9.8)×100
= 784Joule
Thus, we can conclude that the work done on the car is 784Joule.
Learn more about the work done here:
brainly.com/question/25573309
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Answer:

Explanation:
Radius of the pollen is given as

Volume of the pollen is given as



mass of the pollen is given as


so weight of the pollen is given as



Now electric force on the pollen is given



now ratio of electric force and weight is given as


Answer:
2km
Explanation:
Given data
We are told that the direction traveled are
North>>>East>>>South
Hence the displacement is defined as the distance away from the initial position is
Initial position =18km
FInal position = 16km
The displacement = 18-16= 2km
Hence the displacement is 2km