Asked by bhdrkn 5 years ago

The coefficient of static and kinetic frictions between a 3.0-kg box and a desk are 0.40 and 0.30, respectively. What is the net force on the box when a 15 N horizontal force is applied to the box?

What is the minimum speed of the ball at the bottom of its swing (point B) in order for it to reach point A, which is 1.0-m above the bottom of the swing?

Vector A is 75.0 cm long and points at 30° above the positive x axis. Vector B is 25.0 cm long and points along the negative x axis. Vector C is 40.0 cm long and points at 45° below the negative x axis

A) Determine the x and y components of Vector B.

B) Determine the sum of these three vectors in terms of magnitude and direction.

C) Determine the sum of these three vectors in terms of components.

D) Determine the x and y components of Vector C.

E) Determine the x and y components of Vector A.

For a spacecraft going from the Earth toward the Sun, at what distance from the Earth will the gravitational forces due to the Sun and the Earth cancel?

A 0.10-kg object with a velocity of 0.20 m/s in the +x direction makes a head-on elastic collision with a 0.15 kg object initially at rest. What is the final velocity of the 0.10-kg object after collision?

A stone is thrown horizontally with an initial speed of 10 m/s from the edge of a cliff. A stop watch measures the stone's trajectory time from the top of the cliff to the bottom to be 4.3 s. What is the height of the cliff?

Two boxes are connected by a cord running over a pulley as shown in Fig. 1. Box I of mass 8.0 kg rest on the top of the table; the coefficient of kinetic friction between box I and the table is 0.10. Box II has a mass of 15.0 kg.

(a) Calculate the acceleration of the system.

(b) Calculate the tension in the cord.

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**Chap. 7, #10.** (II) A 3800-kg open railroad car coasts along with a constant speed of 8.60 m/s on a level track. snow begins to fall vertically and fills the car at a rate of 3.50 kg/min. Ignoring friction with the tracks, what is the speed of the car after 90.0 min?

**Chap. 7, #16.** (II) A 12-kg hammer strikes a nail at a velocity of 8.5 m/s and comes to rest in a time interval of 8.0 ms.

(a) What is the impulse given to the nail?

(b) What is the average force acting on the nail?

**Chap. 7, #32.** (II) A 28-g rifle bullet traveling 230 m/s buries itself in a 3.6-kg pendulum hanging on a 2.8-m-long string, which makes the pendulum swing upward in an arc. Determine the vertical and horizontal components of the pendulum's displacement.

**Chap. 7, #36.** (II) A ball is dropped from a height of 1.50 m and rebounds to a height of 1.20 m. Approximately how many rebounds will the ball make before losing 90% of its energy?

**Chap. 8, #5.** (II) A child rolls a ball on a level floor 3.5 m to another child. If the ball makes 15.0 revolutions, what is its diameter?

**Chap. 8, #8.** (II) A rotating merry-go-round makes one complete revolution in 4.0 s (Fig. 838).

(a) What is the linear speed of a child seated 1.2 m from the center?

(b) What is her acceleration (give components)?

**Chap. 8, #18.** (II) A wheel 33 cm in diameter accelerates uniformly from 240 rpm to 360 rpm in 6.5 s. How far will a point on the edge of the wheel have traveled in this time?

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**Chap. 8, #24.** (II) Calculate the net torque about the axle of the wheel shown in Fig. 839. Assume that a friction torque of 0.40m-N opposes the motion.

physics

Answered by DVick 5 years ago

**What is the net force on the box when a 15 N horizontal force is applied to the box?**

*static friction is overcome because*

$$ f_s mg = (0.4)(3.0)(9.8) = 11.76 < 15$$

*then,*

$$F_{net} = \sum F = 15+f_k N = 15+f_k mg$$

$$=15-(0.3)(3.0)(9.8)=6.2 \text{ N}$$

$\ldots$

**Excerpt from file: **Physics Tutorial The coefficient of static and kinetic frictions between a box and a desk are and , respectively. What is the net force on the box when a 15 N horizontal force is applied to the box? static friction is overcome because, ( )( )( ) then, ( )( )( ) What is the minimum speed of the ball

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