If this object is moving at constant velocity, choose two correct condtions.
f=G and N=F
N=G and F=f
N=f and F=G
none of above
Assume the mass of object is m. If this object is accelerating to horizontal right with acceleration a, choose two correct condtions.
N=G and F-f=ma
N=G and F=f
N=G and f-F=ma
N-G=ma and F=f
Assume the mass of the object is 10kg. And the object only moves at horizontal direction. Calculate the normal force.（填空题全部不要带单位）
（上一问摩擦力=20N）Assume the mass of the object is 10kg. And the acceleration of the object is 1 m/s2 to right. Calculate F.
Calculate the Fpull component（分解的量） in y-direction.
F
F×cosθ
F×sinθ
F×tanθ
In y-direction, we can get which one of formula? (N=normal force, G=weight)
F×sinθ+G=N
N=F×sinθ
F×sinθ+N=G
N=G
In x-direction, if the 20kg object moving to right with acceleration 5 m/s2. We can get which one formula?
F×cosθ+G=N
F×cosθ-f=100
F×cosθ=f
f-F×cosθ=100
In y-direction, we can get which one of formula? (N=normal force, G=weight)
F×sinθ+G=N
N=F×sinθ
F×sinθ+N=G
N=G
If the object is slide downward（下滑）, which force cause this happen?
no force need
N
f
G
Draw the x and y direction are correct or incorrect?
x-direction is correct
x-direction is incorrect
x and y are all correct
x and y are all incorrect
calculate the component of weight in x-direction.
G×cosθ
G×sinθ
G×tanθ
G
calculate the component of weight in x-direction.
G×cosθ
G×sinθ
G×tanθ
G
Assume the 20kg object is stationary, θ=30°, calculate the normal force. （保留整数）
Assume the 20kg object is stationary, θ=30°, calculate the frcition force. （保留整数）
假设两根绳子的拉力对称，且物体处于平衡状态那么下列哪一项说法正确
两边θ不一样
重力=2*拉力*sinθ
重力=2*拉力*cosθ
以上都不正确
重力=拉力*cosθ
重力=拉力*sinθ
假设两根绳子的拉力对称，且物体处于平衡状态,假如拉力=100N，且θ=60°，请问物体的重力为多少？
假设物体处于平衡状态，那么下列哪个式子正确？
T1=T2
T1=T2*cosθ
T1=T2*sinθ
T1=mg
T2*sinθ=mg
假设物体处于平衡状态，T2=100N,且θ=45°，请问T1=？保留整数，不带单位
假设物体处于平衡状态，T2=100N,且θ=45°，请问物体重力=？保留整数，不带单位
请问这个过程中变化的速度（velocity）=？
请问这个过程中球受到球拍的力=？（50ms=0.05s,答案保留整数）