A skier and her skies have a total weight of 545 N. If it takes a horizontal force of 38.0 N to start moving on wet snow on level ground, calculate the coefficient of static friction for the skies on wet snow.
Fg
545
Fn
38.0
us
A car of weight 1500 N has its brakes locked. Calculate the force (in N) needed to begin to drag the car on dry asphalt (in the coefficient of static friction on this material is 1.200).
Fn
1500
us
1.200
Ffr
An 80 kg skier is using waxed hickory stis on wet snow (coefficient of kinetic friction is 0.14). Calculate the force of friction (in N) on the skis as the skier glides along the level.
m
80
uk
0.14
Ffr
A lift truck with rubber tires has a mass of 1640 kg. What is the force of kinetic friction (in N) when the lift truck skids on wet concrete with all four wheels locked if the coefficient of kinetic friction is 0.5000 and g = 9.800 N/kg [down]?
Fn
16100
uk
0.5000
Ffr
A force of gravity of 20 N [down] acts on a book at rest on a rough level table. A horizontal force of 12 N is needed to just start the book moving across the table. Calculate the coefficient of static friction.
Fn
20
Ffr
12
us
A 1000 kg crate is dragged across a rough level floor. A force of 450.0 N is needed to drag the crate at constant speed. Calculate the coefficient of kinetic friction between the crate and the floor, assuming g = 9.800 N/kg [down].
Fn
9800
Ffr
450.0
uk
With the tank full of gasoline, a motorcycle and its rider have a weight of 2350 N. Calculate the force of kinetic friction (in N) between the rubber tires and dry concrete (the coefficient of kinetic friction is 0.7000) when the motorcycle skids with both wheels locked.
Fn
2350
uk
0.7000
Ffr
A force of 31 N pulls an 8.0 kg steel slider at a constant speed along a horizontal steel rail. What is the coefficient of kinetic friction of steel on steel ig g = 9.8 N/kg [down]?
Fn
78.4
Ffr
31.0
uk
A student decides to go hiking. First he walks 6.0 km [E] om 2.0 h, then he walks 8.0 km [N] in 4.0 h. Calculate his average velocity (in m/s [N 37 degrees E]).
d
10000
t
21600
v
A cyclist covers 20 km [W] in 1.5 h and then 15 km [s] in 2.0 h to reach a rest area. Calculate the average velocity (in m/s [S 53 degrees W]).
d
25000
t
12600
v
A circus van moves 50 km [E] in the first hour, 40 km [W] in the second hour, and 30 km [N] in the next half hour. Calculate the average velocity (in m/s [N 18 degrees E]) of the travelling circus van.
d
32000
t
9000
v
A delivery van, parked 2.0 km [E] of a police car, moves to a position 6.0 km [E] of the police car in 180 s. What was the average velocity (in m/s [E]) of the delivery van?
d
8000
t
180
v
A student is ten-pin bowling with her friends. She gives a 7.0 kg bowling ball an acceleration of 5.0 m/s^2 [forward]. Calculate the net force (in N [forward]) she exerts on the ball.
m
7.0
a
50
Fnet
A curler exerts a force forward on a 19 kg curling stone and gives it an acceleration of 1.8 m/s^2 [forward]. Calculate the value of the net force [in N [forward].
m
19
a
1.8
Fnet
A truck skidding on wet asphalt has a mass of 2000 kg. The total force of kinetic friction of the asphalt on the tires is 1000 N [back]. Calculate the deceleration (in m/s^2 [backward]) of the truck.
m
2000
Fnet
100
a
The net force on a 6.0 kg grocery cart is 12 N [S]. Calculate its acceleration (in m/s^2 [S])
m
6.0
Fnet
12
a
In a road test, an automobile is given an acceleration of 2.7 m/s^2 [E] by a net force of 4.2 x 10^3 N [E]. Calculate the mass (in kg) of the car.
a
2.700
Fnet
4200
m
What net force (in N [S]) is needed to accelerate a 208 kg motorboat at 3.61 m/s^2 [S]?
m
208
a
3.61
Fnet
A driver and his motorcycle have a combined mass of 280 kg. They accelerate from 70.0 m/s [E] to 340 m/s [E] in 42.0 s. What is the net force (in N [E]) on the driver and his motorcycle?
m
280
v1
70.0
v2
340
t
42.0
Fnet
A net force of 2.20 x 10^2 [W] applied to an object increases its velocity from 80.0 m/s [W] to 240 m/s [W] in 54.0 s. What is the mass (in kg) of the object?
Fnet
220
v1
80.0
v2
240
t
54.0
m
A child is riding her bicycle on dry conrete at a velocity of 120 m/s [E] when she puts on her brakes. The bicycle and the child have a combined mass of 70.0 kg, and the friction exerted by the pavement on the brakes locked is 235 N [back]. What is the child's velocity at the end of 20.0 s?
v1
120
m
70.0
Fnet
235
t
20.0