The attached diagram shows the motion of crate on a single line The forces acting on it have been resolved as shown in the attached figure.The kinetic friction opposes the motion.Now crate is moving with constant speed so the acceleration is constant.

Applying Newton's second law to determine the force F and also substituting the values for $F_{k}$ to eliminate normal force

$$\sum_$ F = ma

Now $a_{x}$ and $a_{y}$ components are zero

Horizontal and vertical forces are Force on crate, weight of crate and kinetic friction

$$\sum F_{x} = Fcos\theta-f_{k}-mgsin\theta=0$

$$\sum F_{y} = F_{n}- Fsin\theta-mgcos\theta=0$

therefore $f_{k} = \mu_{k} F_{n}$

$Fcos\theta- \mu_{k} F_{n}-mgsin\theta=0$ >>> (1)

$F_{n}=Fsin\theta+mgcos\theta$

By putting the above equation in equation 1 we get F

$F=\frac{mg(sin\theta+\mu_{k}cos\theta) }{cos\theta-\mu_{k}sin\theta }$

By putting values we get

F = $\frac{(80kg)(9.81\frac{m}{s^{2} })(sin36+(0.8)cos36) }{cos36-(0.8)sin36}$

F= 2860.8 N

F= 2.86KN

4 0

4 years ago

Explain what nuclear fusion is in the role it plays in Stars. DO NOT LOOK UP ANSWERS

Aloiza [94]

Answer:

Stars are powered by nuclear fusion in their cores, mostly converting hydrogen into helium. The production of new elements via nuclear reactions is called nucleosynthesis. A star's mass determines what other type of nucleosynthesis occurs in its core (or during explosive changes in its life cycle).

8 0

3 years ago