Q: If a space station is placed in a circular orbit around Earth at a distance of $$5.00 \times 10^6$\ \mathrm{m}$$ above the surface, what is the gravitational force on a $$5000\ \mathrm{kg}$$ astronaut inside?

$$4.21 \times 10^4$\ \mathrm{N}$$

Question 1

A 1000-kg car is moving at 30 m/s around a horizontal unbanked curve whose diameter is 0.20 km. What is the magnitude of the friction force required to keep the car from sliding?

Accepted Answer

$$9000\ \mathrm{N}$$

Question 2

A stone with mass $$1.0\ \mathrm{kg} is $$tied to the end of a light string, which keeps it moving in a circle with a radius of $$0.50\ \mathrm{m} at a $$perfectly smooth horizontal plane. If the stone makes one full rotation every $$0.40\ \mathrm{s}$$, what is the tension in the string?

Accepted Answer

$$31.4\ \mathrm{N}$$

Question 3

If the work done to stretch an ideal spring by $$6.0\ \mathrm{m} is$$ $$7.5\ \mathrm{kJ}$$, what is the spring constant (force constant) of this spring?

Accepted Answer

$$7500\ \mathrm{N/m}$$

Question 4

A $$5.0\ \mathrm{kg}$$ boy uses energy to run up a flight of stairs that is $$10.0\ \mathrm{m}$$ high. If he runs up in $$8.0\ \mathrm{s}$$, what is his average power output?

Accepted Answer

$$735\ \mathrm{W}$$

Question 5

An astronaut in an earth satellite feels weightless because:

Accepted Answer

The astronaut is falling.

Question 6

A $$700\ \mathrm{m}$$ radius space station rotates so that the astronaut standing inside experiences $$1\ \mathrm{RPM}. $$What is the minimum period $$T in $$seconds?

Accepted Answer

$$733\ \mathrm{s}$$

Question 7

What is the radial acceleration on the astronaut standing inside the space station in terms of $$g if $$the tangential speed is $$7.68\ \mathrm{m/s}$$ and the radius is $$700\ \mathrm{m}$$?

Accepted Answer

$$0.783\ g$$

Question 8

A car of mass $$80\ \mathrm{kg} is $$released from rest at a height of $$6.0\ \mathrm{m}$$ above the bottom of a vertical loop of radius $$20.0\ \mathrm{m}. $$What is the speed of the car at the top of the loop?

Accepted Answer

$$19.8\ \mathrm{m/s}$$

Question 9

At the top of the loop, what is the normal force on the car if its mass is $$80\ \mathrm{kg}$$ and its speed is $$19.8\ \mathrm{m/s}$$?

Accepted Answer

$$490\ \mathrm{N}$$

Question 10

A $$5.0\ \mathrm{kg}$$ block slides up a $$30^\circ$$ incline with kinetic friction $$\mu_k = 0.20$$ between the block and the surface. If the block starts with a speed of $$6.28\ \mathrm{m/s}$$, how high above the ground does it travel up the incline?

Accepted Answer

$$0.259\ \mathrm{m}$$

Question 11

Two cars, each of mass $$m$$, collide head-on at $$30\ \mathrm{mph}$$ each. If the collision is perfectly inelastic, what is the final velocity of the combined mass?

Accepted Answer

$$0\ \mathrm{mph}$$

Question 12

A $$5.0\ \mathrm{kg}$$ block moving at $$6.28\ \mathrm{m/s}$$ collides with a stationary $$7.0\ \mathrm{kg}$$ block. If the collision is perfectly inelastic, what is the final velocity of the combined mass?

Accepted Answer

$$2.62\ \mathrm{m/s}$$

Question 13

A $$5.0\ \mathrm{kg}$$ block moving at $$6.28\ \mathrm{m/s}$$ collides with a stationary $$7.0\ \mathrm{kg}$$ block. What is the loss in mechanical energy due to the collision?

Accepted Answer

$$57.4\ \mathrm{J}$$

Question 14

A $$5.0\ \mathrm{kg}$$ block moving at $$6.28\ \mathrm{m/s}$$ collides with a stationary $$7.0\ \mathrm{kg}$$ block. What is the magnitude of the impulse delivered to the $$7.0\ \mathrm{kg}$$ block?

Accepted Answer

$$610\ \mathrm{N \cdot s}$$

Question 15

A $$5.0\ \mathrm{kg}$$ block slides up a $$30^\circ$$ incline with kinetic friction $$\mu_k = 0.20$$ and initial speed $$6.28\ \mathrm{m/s}. $$What is the work done by friction as the block travels up the incline for a distance $$L$$?

Accepted Answer

$$W_f = -\mu_k m g \cos(30^\circ) L$$

Question 16

A $$5.0\ \mathrm{kg}$$ block slides up a $$30^\circ$$ incline with kinetic friction $$\mu_k = 0.20$$ and initial speed $$6.28\ \mathrm{m/s}. $$What is the equation relating the initial kinetic energy, work done by friction, and the change in potential energy?

Accepted Answer

$$KE_i + W_f = m g h$$

Question 17

A $$5.0\ \mathrm{kg}$$ block slides up a $$30^\circ$$ incline with kinetic friction $$\mu_k = 0.20$$ and initial speed $$6.28\ \mathrm{m/s}. $$What is the vertical height $$h$$ reached by the block?

Accepted Answer

$$0.259\ \mathrm{m}$$

Question 18

If a space station is placed in a circular orbit around Earth at a distance of $$5.00 	imes 10^6$\ \mathrm{m}$$ above the surface, what is the gravitational force on a $$5000\ \mathrm{kg}$$ astronaut inside?

Accepted Answer

$$4.21 	imes 10^4$\ \mathrm{N}$$

exam two - exan 2 practice test

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드