Answer:
v=2.42m/s
Explanation:
We use the energy conservation theorem in order to solve the problem. The energy when the spring is compressed is equal at the energy when the disk leaves the spring:
At the beginning the initial energy is totally potential, energy linked to the compressed spring. At the end the energy is totally kinetics
We solve the equation in order to find the speed.
k=162 N/m
x=7 cm=0.07m
m=0.135 kg
Answer:
0.63
Explanation:
We are given that
Radius of earth,
Radius of orbit A,
Radius of orbit B,
We have to find the ratio of the potential energy of satellite B to that of satellite A in orbit.
Potential energy of orbit A=
Potential energy of orbit B=
Hence,the ratio of the potential energy of satellite B to that of satellite A in orbit=0.63
Answer:
Puesto que la energia cinética traslacional es mucho mayor que la capacidad del chaleco antibalas, la bala atravesaría el chaleco antibalas.
Explanation:
Un chaleco antibalas soporta el disparo de una bala disipando la energía de esta última a través de su propio material. Si sabemos que el chaleco antibalas soporta 120 joules de energía, cabe saber si la energía cinética traslacional es igual o inferior a ese límite, significando que la bala no atravesaría el chaleco.
La energía cinética traslacional de la bala (), in joules, queda expresada con la siguiente fórmula:
(1)
Donde:
- Masa de la bala, en kilogramos.
- Rapidez de la bala, en metros por segundo.
Si sabemos que y
, entonces la energía cinética traslacional de la bala es:
Puesto que la energia cinética traslacional es mucho mayor que la capacidad del chaleco antibalas, la bala atravesaría el chaleco antibalas.
Answer:
: Work done by horizontal force
: Work done by friction force
: Net work
Explanation:
Work theory
Work is the product of a force applied to a body and the displacement of the body in the direction of this force.
Thus. The work is equal to the product of the force by the distance (d) and by the cosine of the angle ( α) that exists between the direction of the force (F) and the direction that travels the point or the object that moves:
W= F*d*cosα Formula (1)
The work is positive (W+) if the force goes in the same direction of movement.
The work is negative (W-)if the force goes in the opposite direction to the movement
Net work (Wn)
Net work is defined as the sum of the work done from an initial place to an end point of the trajectory, for each of the individual forces to which the system is subjected.
Problem development
We determine the forces that perform work:
in formula (1 )we observe that the forces that perform work are the forces parallel to displacement. that is α = 0.
For this case they are the horizontal force (F) and the frictional force (Ff)
F=31.3 N : Horizontal force
Ff=μk*N , μk:coefficient of kinetic friction , N : Normal force
N=W
W: block weight W= m*g, m: block mass , g: acceleration due to gravity
W= 4.30 kg* 9.8 m/s² = 42.14 N
Ff= 0.599*42.14 N= 25.24 N : Frictional force
Calculating of the Net work (Wn)