3000 N of friction exists between the bear and the tree.
The bear goes down at a constant speed, thus there is no acceleration. The forces add up to zero. As a result, upward friction and downward weight result in zero
i.e.,
F-mg=0
F = mg
F = (300 kg)/10
(gravitational acceleration)
3000 N frictional force equals F.
How does friction force work?
- Friction is the force that prevents two solid objects from rolling or sliding over one another. Even though frictional forces, such as the traction required to walk without slipping, may be advantageous, they can also be a significant hindrance to motion.
Between solid surfaces, there are three basic types of friction:
- Rolling
- Sliding.
- Static. They are graded from strongest to weakest. Fluid friction happens when liquids or gasses are mixed together.
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Answer:
- 2.425 x 10^5 J
Explanation:
The gravitational potential energy between earth and the bock is given by

Where, G is the universal gravitational constant = 6.67 x 10^-11 Nm^2/kg^2
M is the mass of earth = 5.8 x 10^24 kg
m is the mass of block = 4 kg
r be the radius of earth = 6380 km = 6380 x 10^3 m
by substituting the values in the above expression, we get

U = - 2.425 x 10^5 J
We consider the momentum in the x-direction and apply the principle of conservation of momentum to form the equation:
m(A)u(A) = m(A)v(A) + m(B)v(B), since u(B) = 0 as B is at rest
We calculate v(A) using:
Vx = Vcos∅
Vx = 2.1cos(30)
Vx = 1.82 m/s
1.5 x 4.5 = 1.5 x 1.82 + 3.2v(B)
v(B) = 1.26 m/s
The deflection angle of B will be 30° above the positive x-axis, so:
v(B) = Vcos∅
V = 1.26 / cos(30)
V = 1.45 m/s
The velocity of B is 1.45 m/s
Answer:
False.
Explanation:
No. Voltage does not alternate between zero and positive or negative. In non return signaling (NRZ) voltage at zero represents the 0 bit and at the positive represent the 1 bit. NRZ is one of the signal levels of uni polar Scheme in which the signal does not return to zero at the middle of it. For example 10110. That is why it named as the non return signaling.
Answer:
-7.14
Explanation:
According to equation of motion
v = u + at
where
v is the final velocity at any time t
u is the initial velocity
a is the acceleration
and t is the time
___________________________________________
Given
An object is thrown upward it means
its initial velocity is in upward direction
but acceleration due to gravity is in downward direction which will cause to decrease the velocity of object.
Intial velocity u = 31.1 m/s
final velocity v at 4 second we have to find.
t = 4 second
a = g = 9.81 m/s2 (it is acting in opposite direction of motion hence its sign will be negative ).
Thus
a = - 9.81 m/s2
using the above values in v = u + at
v = 32.1 - 9.81*4
v = 32.1 - 39.24
v = -7.14
Thus, correct option is -7.14.