Binh can dua 1 cai thung len cao bang mat phang nghieng. Cai thung nang 40kg ma luc keo toi da binh chi dat duoc 80N. Theo em binh nen dung mat phang nghieng cang dai hay cang ngan de co loi the ve luc vi sao

tai sao khi dung mat phang nghieng don bay hay rong roc de dua vat len cao lai de dang hon khi dung tay keo vat theo phuongthang dung?

Cau 1 : Dat quyen sach len ban . Co nhung luc nao tac dung len no ?

Cau 2 : Co 3 qua can , nang lan luot la 50g , 30g , 100g o ben nay . Co 3 goi keo o ben kia . Tinh can nang 1 goi keo ?
Cau 3 : Cho  truoc mot cai dia , mot binh chia do , mot cai bat va mot hon da  , hon da do ko lot vua binh chia do . Hay neu cac buoc de do the tich hon da

de dua 1 vat nang co khoi luong 30 kg len tang 2 cua nha ma giam ve luc thi ta dung rong roc gi ? ve hinh minh hoa

De keo 1 thung hang co khoi luong 2 ta len cao theo phuong thang dung thi phai dung luc nhu the nao ?

co hai doi keo co hay cho biet:

- luc ma hai doi tac dung len soi day la luc keo hay luc day?

- luc do doi ben trai tac dung len day co phuong va chieu nhu the nao?

- neu soi day dung yen thi luc tac dung cua hai doi len soi day co dac diem gi?

Mot nguoi su dung rong roc dong dua khoi be tong 100kg len cao.tinh luc keo toi thieu cua nguoi do khi dua khoi be tong len cao.

trong truong hop khan cap, nguoi lai xe co the phan ung nhanh va dap nhanh. neu mot xe dang chay voi toc do 20m/s, nguoi lai xe phat hien ra vat can phia truoc va mat 0,6s de phan xa va dap nhanh. trong khoanh thoi gian nay xe di duoc quang duong bao nhieu? sau khi dap phanh, xe co dung lai ngay lap tuc hay hk?